We have eaten off site a fair few times... my top recommendations would be Tony Roma's on I-Drive for some nice ribs, Cheesecake Factory at Mall at Millenia (although it is a long long drive from WDW and may be too far - if you double it with a trip to Florida Mall you're most of the way there, or go look around Millenia Mall), in the same area is the excellent chinese P F Chang's China Bistro (totally yummy)
Other I-Drive - this year we tried Ming Court Chinese. I really didn't love it, but it could have been worse - food was average to good, but atmosphere terrible. Olive Garden does some reasonable pasta (I am fussy about Italian food). Cafe Tu Tu Tango is meant to be great - we are going there in December.
For an easy but not quite off-site meal, I second the suggestion of Benihana at the Hilton by Downtown Disney. It's a hibachi-grill teppanyaki restaurant. We love it becuase here in the UK it is really expensive, but the US is SO much cheaper! The steaks, chicken, shrimp are all awesome...
We have also eaten at Bubba Gump in Citywalk, which was brilliantly themed, good fun, but not outstanding food, and Hard Rock Cafe, which is again, good but not amazing.
Other places we plan to try off site are Coq au Vin and Roys that both get good write ups on trip advisor!
Happy eating!
Miranda
