It's a shame that your initial experience with Harvest Hosts wasn't a good one and I'd be interested to know what went wrong. We haven't tried RV Overnights yet, but may look into it.
As you know, the View and Via share the same chassis, but the bodies are completely different. Our view is also 6 years older than your Via, and systems changed somewhat in the interim. I looked at the 2016 Via owner's manual online (I was curious about it) and the two versions - the 25P and 25T are equipped quite differently; which do you have? Since you purchased it recently, it must be pre-owned, so did the original owner make any electrical modifications to it? Does your Via have any solar capability? It's important to establish a baseline before planning any upgrades.
You should also take some time to define your goals for an electrical upgrade. Do you simply want to be able to boondock for a night or two, using the lights, fans, radio, TV, water pump, etc., without having to worry about your battery capacity, or do you want more extended and/or expanded capability? Per your request, I'll explain our upgrade, then review some options for you. Buckle your seatbelt...
Our View had only a pair of 85Ah lead-acid batteries, a 45-amp converter/charger, no inverter, and no solar. This got us through overnights without any issues, but we only ran the basics I mentioned above. My goals for the upgrade were:
- Increase boondocking capability to a week or more under the conditions listed above.
- Be able to run AC-powered devices - microwave, toaster, waffle iron, etc. - off the batteries.
- Be able to run the air conditioner (A/C) for at least a couple of hours on batteries, if need be.
This required pretty extensive upgrades, particularly for the ability to run the A/C, as it draws a lot of power.
I am absolutely not suggesting that you need to do anything like this, but you did ask for details. I ended up installing the following:
- 600Ah of lithium (LiFePO4) batteries. I started with 300, but added a second 300Ah battery after our first trip post-upgrade. This required relocating the batteries (and substantial rewiring), as they wouldn't fit in the stock battery box. However, 200-300Ah of batteries would fit in the battery box easily.
- A 60-amp DC-DC charger. This was necessary because the large lithium battery bank can draw very high current from the alternator, which could cause it to overheat and fail. This is not an issue with batteries up to ~200Ah. The DC-DC charger also bumps up the charging voltage to fully charge the lithium batteries.
- An upgraded 75-amp converter charger. The original charger would not output sufficient voltage to fully charge the lithium batteries. Since I needed to change the converter, it made sense to go up in capacity as well. This required a minor wiring upgrade.
- A 3000-watt inverter with a built-in automatic transfer switch. This is really the minimum necessary to power the A/C. While it doesn't draw more than 1600 watts, a 2000 watt inverter might not do the job and wouldn't leave enough capacity to run additional AC appliances at the same time.
- A soft starter for the A/C unit. This reduces the initial startup load when the A/C is turned on, easing the load on the inverter. It also makes the startup quieter.
- An upgraded (400-amp) main battery fuse.
- A battery cutoff switch. The switch in the door well turns off most of the DC circuits, but not everything. The cutoff switch disconnects the batteries completely, which is sometimes necessary when working on the system.
- I also installed a Victron Lynx Distributor as the central connection and fusing point for all of the DC connections. For my particular installation, this made the most sense.
- A cooling fan for the inverter. This was necessary due to the confined area where it's located.
After installing the new batteries under the dinette seat, I refurbished the original, rusty battery box. After cleaning and repainting it, I sealed the openings on the sides and build an air screen/filter for the bottom, as this is now the location for the inverter, Lynx distributor, cooling fan and battery cutoff switch.
I opted to not install any solar at this time, due to the way we use our View. That could change.
Hopefully, I haven't scared or overwhelmed you with all of this. While this upgrade achieved our goals with room to spare,
most of the above wouldn't be necessary if your goals are more modest than ours were.
Let's look at some options for you. I'll assume that your Via has the stock stock setup of 2, 100Ah lead-acid batteries, which provide you with ~100Ah of usable power, since they shouldn't be drained past 50% on a regular basis.
If your goals are modest, an upgrade to 200Ah of lithium batteries may be all you need. Since the full power of lithium batteries is usable, that will effectively double your capacity, while also eliminating battery maintenance and cutting the battery weight in half. It will provide sufficient power for 2-3 days of light power use, as previously outlined. The new battery - or batteries - will fit where your current batteries are located and shouldn't require any wiring upgrades, though they may require different connectors.
You'll have the choice of installing a pair of 100Ah batteries or a single 200Ah battery. The single battery will be smaller overall, less expensive, and lighter. However, using a pair provides redundancy in the unlikely event that one fails, and will use the stock wiring arrangement and hold-downs. If you want to go larger, a single 300Ah battery will fit, but anything larger than that probably won't.
I don't know if your Via's converter has a lithium setting or if there is a lithium upgrade module for it. I suggest that you contact the manufacturer and ask them. If it isn't lithium compatible, it will still work, but will only charge the batteries to ~80-85%, so you'd lose some of your battery capacity gain. Replacing the converter is a relatively easy project. If you stick with the same brand, it should be a wire-for-wire swap. If you stick with the same capacity, you can use the stock battery and ground wiring. If there's a lithium module for your existing converter, that should be easier and cheaper.
You have a 220-amp alternator, which should handle the charging load from 200Ah of lithium batteries without the
need for a DC-DC charger, but it won't provide the voltage needed to charge them to 100%. If you decide to go larger than 200Ah of batteries, I would definitely install a DC-DC charger.
If you have solar installed, the solar controller may have a lithium battery setting. If so, the solar could be used to "top off" your batteries if your converter and alternator can't fully charge them.
The bottom line is that simply upgrading the batteries can be a drop-in installation, depending on your current equipment.
Depending on the model you have, your Via may have an inverter installed. If not, it may be prepped for one, but that's beyond my knowledge. Whether you need inverter capability - running AC appliances off the batteries - is up to you.
BTW, as for my "wisdom", let's just call it experience.

I'm still relatively new to this and learning all the time. I just hope this helps provide some useful information.