How to Find Parks?

I have been using RV Life Campground Reviews for years. I like it as not only can you find the place it also gives many years of reviews for the campground you are looking at

https://campgrounds.rvlife.com/

The others out there are good also rvparky was mentioned. Good Sam also has a sight. I think once you find a sight you like and is user friendly to you, you will stick with that sight.

Good Luck

Mostly googling.

Campendium.com is pretty good.

If we are on the move, we use Passport America for the savings more than finding. PPA isn't as good when staying somewhere more than a night or two (we'll still check but usually they have limits)

We are traveling longer term mostly, so we are quite flexible on where we stop. If it was a week or two vacation, we would place more emphasis on prime location as you have limited time, so driving from a 1/2 hour away to see a national park or other site may be less acceptable and in the big picture represent a small portion of the trip cost.

RV Trip Wizard RVTW which is a planning tool has many thousands of parks and is linked to Campground Reviews which has all of those parks listed usually with reviews and pricing.
RVTW
Campground Reviews

Those are mainly for commercial and park campgrounds not boondocking sites which is a whole different matter.

Or simply use google maps, select an area, town and add campgrounds/rv parks near xxxx.

There are numerous apps
RVParky
Ultimate campgrounds
www.recreation.gov
If you are eligible, www.militarycampgrounds.us
try the app store, google or apple, you will find many.