Welcome to the forum and congrats on your first RV.
I agree, keep the original type water heater. They do a good job.
For your first outing, if possible, camp in your (or a friend/relative's) driveway or yard. If not possible, go to a local campground.
That way you will be close to home when you realize you forgot something. It will allow you to become more familiar with the RV in a more familiar setting.
Also, check your roof. A small leak can cause a lot of damage if not repaired quickly. Look for missing/loose caulk or any holes/tears.
Sometimes a low hanging branch can cause a little damage.
They are easily repaired with
Eternabond and
Dicor Self Leveling Lap Sealant. You can find them on several websites and most RV stores sell the products. Shop around for the best prices.
Enjoy your travels.