You are on the right track. Your reservoir should be behind the steps. On the lip of one of the steps, underneath, there should be a nut holding the step. Remove it and the step should lift up and give access to the reservoir. You should also see a series of hydraulic hoses on one side or the ohter.
On the top of the reservoir will be a 1 inch or more nut. Unscrew it and you will see a small dip stick. It will give you a reference of the liquid in the reservoir. Your leak indicated it was pink so that is good but without a leak, stick your finger in the hole, pull it out and drip on a paper towel. It should be pink. Most don't ever use the dip stick. Instead we stick our index finger in the hole until the first knuckle is at the bottom ridge of the opening. Fluid should just be touching the finger tip.
Only check with the slides in and the jacks retracted.
Another practice is checking for debris in the reservoir. Use a turkey baster and insert it in the fluid down to the bottom. Stir it up and then suck up some fluid. Go to your wife's flower bed and squirt the fluid on a paper towel look for any sediment or rust particles. If a lot, the system should be flushed. Sediment or rust can wedge between a seal and cause a leak.
Oh, don't tell the wife you used her turkey baster and blame the birds on the pink flowers.
Here is the operating manual
for one of the Journey models Winnebago makes.
DO NOT USE brake fluid or hydraulic jack fluid. Use of these can damage seals. Check the manual.