Are you going to have a car?
If not, I really wouldn't suggest depending on hotel shuttles if you have younger children. With the exception of DTD hotels, the offsite shuttles aren't anything like the WDW shuttles. You can't even compare them. They often only come 2 times in the morning, 2 times mid day, and 2 times at night. If you need to leave before the next scheduled shuttle, you'll have to take a cab.
I used the offsite shuttle on a "budget trip" one time. Never again. I decided that if I couldn't afford to rent a car, then I would save up until I could. It usually took over an hour to get back to our hotel in the evening, and we often ended up not seeing the fireworks since the busses last pick-up was before the shows ended. We actually prefer to drive to the parks even when we stay onsite. I don't like waiting for a bus at the end of the day.
Depending on the timing of your visit, you should be able to rent a small car for under $200 for the week. You can use Priceline for the car and save even more. Plus if you have a car, you can eat offsite and save a bundle as well.
There are lots of hotel choices in the $55 - $95 per night range. You might consider the Sheraton Safari. I think it would be every bit as nice as the Radisson, and a little less expensive.
Good luck!
Lisa
