Congratulations MookieKat. You have set the record for the most number of posts, on this forum, since you joined 8/24/13 (98). It's great to ask questions about a large purchase.
Here is my response to most of your questions.
1. Get a slide or two
2. camped in state parks for 25 years, no problems with slide space
3. get a smoothed wall camper; easier to keep clean
4. mold comes from leaking campers, keep up on maintenance of the rv, esp the roof, no leaks; not mold
5. gassing off will occur in any new camper no-matter what the dealer tells you
6. interest rates based on your credit
7. one brand better that the other? ALL have problems
8. length of trailer based on your floorplan preference
9. many tow a TT with a Dakota. as long as you match the trucks towing specs
10. all electric is possible with almost any TT
11. it's logical the the lighter rv's don't put a strain on TV but might not tow better than the heavier ones
12. lowest prices at dealers varies with inventory esp leftovers
There's all your info you asked for and more on all your posts answers. Get out to dealers and look. What one person doesn't like my be your favorite brand or model.
Good luck.