My first question is if two days for visiting each park (Universal Studios, Islands of Adventure, and Legoland) is right, or if it is too much. I know my daughter will be thrilled with Harry Potter World and Legoland, but I don't know if two days is too much for Universal Studios.
And the second question is if it is really convenient to stay in an inside hotel, such as we did in Disneyworld.
Thank you very much for your advice, I need it so much!
I think three days is probably enough to see all the highlights at Universal Orlando. You could probably do both parks in just two days if you go on a lightly-attended day or if you stay at one of the three on-site hotels and get front-of-the-line access.
Three days is ideal for Universal Orlando, one for each park and then one day to revisit your favourites (assuming you purchase a park hopper ticket). I don't know much about Legoland, but I know enough to realise one day will be more than enough time to spend there.
I've stayed offsite during peak periods and hit every attraction at Universal Orlando in two days - so if it isn't in your budget, Universal is definitely 'doable' staying offsite. In fact, I have done it in one day without express pass (albeit I missed a couple of lesser attractions). Though I wouldn't advise attempting that - that came around through lots of research and years of experience! If you are planning on doing Universal for two days, or even three, definitely check out some touring plans and adapt them to your own family's priorities and enjoyment. The tour plans on this site are good for hitting most, if not all the major attractions of the parks.
Enjoy your trip!
Walt Disney World's Magic Kingdom
Disney's Animal Kingdom
Disney's Hollywood Studios
Disney California Adventure
Universal's Islands of Adventure
Universal Studios Florida
Universal Studios Hollywood