READ READ READ and then READ some more!
Buying a new camper does NOT equal buying a new car/truck.
Many "New" campers have "issues" (poor quality/craftsmanship) that folks are then stuck with waiting to be resolved. READ
Some of the older units where built much better.
It is next to impossible to find a "good dealership" when you are new to camping. Most EVERY dealership is AWESOME while trying to sell you anything. It is only when you need help AFTER you spent your money do you find out what the dealership is really like.
I bought a used TT from a dealer because of warranty, I thought. As it turned out, they did not want to offer any warranty and AFTER my initial purchase (even before I picked the camper up) they turned into the dealership from HELL.
Friends of mine bought a new TT and had it only a couple of years before they took it on a trip to Alaska. They had so many breakdowns (broken frame, broken leaf springs, etc.) that the camper never made it home with them. They ended up buying something else on the way home.
READ, READ, READ
I LOVE LOVE LOVE my camper and if and when I replace it, I will find another USED camper.
Layout is very important, in my opinion. I have seen layouts where you have to climb over tables and or other occupants to get in and out of bed.
Also, if you get one with tip outs, consider if you will be able to access fridge and toilet while on longer trips. It is nice to be able to access food and such without opening tip outs.
As far as memberships go - I would suggest to get your feet wet first. Try out different kinds for campground to see what you like, then make a decision.
Good luck and enjoy the process!