I've stayed at several offsite properties that meet your needs. Depends what you want to spend, but there are tons of options. For my group of six (wife and I, my parents, 2 kids), we often rent a 2 or 3 bedroom townhome somehwere along the southern I-drive corridor. There are dozens of complexes, and we can usually find something like that for around $125-$175 a night that sleeps all six of us in separate bedrooms, and also includes kitchen, living room, dining area, balcony, etc.
If you're looking for something in the $100/night range, the Buena Vista suites and Caribe Royale Suites are nice places.