We did not have much when we bought our RV as well. We went used and older. We spent $7500 on a 99 TT and yes it needed repairs! It had some water damage in 3 areas. So we had to pull out the bad and replace with good, as well as making sure the roof was nice and sealed! The fridge also was bad, which we found out about 2 months into our trip. So, a new one had to bought. We have been in ours for a couple of years now and since have had to also fix leak in the bathroom tub area and replace rotten bathroom floor from the leak. We have also replaced toilet too. Our a/c also went out last year and this year our heater is making a horrible noise when it turns on :/ So far, we have invested aprox $12000, but imo that isn't bad considering. My biggest advice is to be prepared to repair! However, that doesn't mean not to go over the RV with a fine tooth comb. Look for signs of leaks ( Go during raining season if at all possiable ).Make sure everything has been recently inspected and don't be afraid to climb underneath it and look too. Everything you find wrong will help you negotiate a better price. As long as the bones are good, you can always redo the cosmetic stuff later
As far as what to get, since you have 3 big dogs, have you considered a toy hauler? I am thinking that the back would be nice and open, easy to clean messes and when your home, you could open the back for your dogs to get fresh air/run in an out of
I hope this helps you. Good Luck!