For the sink cover we bought a basic camco cutting board cover. We also got a folding table multipurpose table that when folded fits perfectly on the over hang in the back basement. We used that table for holding things like the coffee maker and other stuff.
We never had a problem getting it leveled....My wife would let me know when I had the tires centered on the blocks....and I kept a bubble level up front that I could throw on the floor to do a quick spot check. The RV is small enough to wiggle around in the camp spots to find the best spot to level.
Your Winnie probably didnt include a windshield cover....
https://www.amazon.com/ADCO-2507-Clear-Windshield-Cover/dp/B003YJK5FY/ref=sr_1_3?s=automotive&ie=UTF8&qid=1488849963&sr=1-3&keywords=class+c+windshield+cover+ford.....We liked the one with the screen cause we could get extra light into the unit.
My fam is my wife, myself and our 2 girls both under 6....no animals. I never had to do a pull away to go to the dump station (came close once), but most of our longer trips were always at full hookup sites. I stayed away from totes just looked like to much work.
We never felt rocking in our 25B....there was slight movement but not like Ive felt in other units. We also didnt spend alot of time inside our rv....we are almost always outside under the awning, hiking, swimming, playground, riding bikes, etc.
It sounds like you are approaching things like we did...the 25B was our first purchase, we didnt want slides or other extras while we were learning the ins and outs. Plus I was sure my kids and wife would enjoy it as much as they have.
We live in the midwest, and almost everywhere requires reservations....the state parks here are booked 6months in advance....our biggest challenge has been the fact we havent been able to be random and just go camping for a weekend without reservations.
If you upgrade in a few years just remember you will have a loss in the wallet, but kids are only kids once.....you've got a vacation home on wheels so go enjoy those memories.
I hope your 25B treats treats you as good as ours did.