Thank you for the responses!
I do understand that with any RV there can be leaks in vents and windows. I can handle those kinds of repairs if they happen, so my main concern is structural leaks, like those that tend to happen in older RVs with aluminum panels, that I want to avoid. This is why I hesitate to commit to looking to buy a dolphin, aside from the fact that I like the look of the Sunrader.
I have been diligently searching Craigslist and everywhere else that I can think of for listings for the past 2 weeks, so I am not concerned with finding one at a fair price, I just want to be sure that I don't have to spend more money than what I buy it for on repairs.
As far as size I am looking for 21 feet or less, and this will be my new home, so I know to look for all working appliances plus holding tanks, water pumps, shower & toilet etc.
Are there any other common issues that people run into that I need to look out for?