The best move you made was considering all the parameters before choosing what to buy. I suggest you spend the bulk of your time finding the right 5th wheel trailer for your needs. Once you narrow it to 1-2 choices, then get back on here with the details of each...and find out what trucks you need to consider to pull it safely. Honestly I am not a fan of brand wars, and dont want to discourage anybody from this lifestyle...but ask as many questions before committing your dollars to either the rv and truck.
best of luck in your search