It's not bad, you may need some specialized trims and sealants, but everything is available on the web if you look.
Here's a link to the slide out floor replacement in our Terry TT, there's a link in my signature to the Lance truck camper rebuild we did.
Forum member JBarca rebuilt an entire Sunline travel trailer, top to bottom due to multiple leaks. John is a great guy but even you are a fast reader,
there is hours of reading here with hundreds of pictures.If you have a place to work and keep the exposed part of the trailer dry, you won't have any problems. I'm handy like you and like anything else new, you take your time, it's nothing complicated. PM me if I can help.