All three resorts are lovely. RPR tends to be the cheapest. It has a tropical, South Seas feel. The rooms are generally smaller and there is no pool slide. But the pool does have a cute water play area. The Hard Rock is our fav. The rooms are a little spacier. The whole place has a hip vibe. The pool is awesome and our son loves the slide. HRH is also the closest to the parks, you can walk in about 8 mins or so. Probably different with a two or three year old though. There's also bus and boat transportation. The Portofino is usually the most expensive and more luxurious, I guess. We have not stayed there.
Staying on site means you get express entrance to the rides by showing your hotel key card. The best perk ever thought of!!
We've only been in Feb (Pres. week) and December (2nd week). Honestly, with FOTL privileges, it doesn't matter! I am sure there is someone who can tell you the slowest times though.
We haven't tried the meal deal, but haven't heard many positive things about it. We may try it for one day of our stay. Not sure.
As far as how many days...I think it's relative. I'll take as many as I can get, but you could probably do it all in 3 days. For me, that's too short. I want to see and do it all--more than once! 4 days is probably ideal...2 for each park. We have ressies for 8 nights this coming Feb!
City Walk is open 11:00 a.m. - 2:00 a.m. according to the website.
Hope this helps a little!