Sleeping Becca said:
1. Rent an
ECV for DH from an outside company and have it delivered to your resort.
2. Your kids are old enough to do things on their own (buddy system of course)

If you want more information about renting
ECVs, follow the link in my signature to the disABILITIES FAQs thread. Post #2 of that thread has information about renting wheelchairs and ECVs.
If your children have a cell phone, that would give you more peace of mind for letting them venture out. Keep in mind though that there is no cell phone reception in some buildings.
I have two experiences that I think you would benefit from hearing.
First, we went to WDW in 2004 with a large group of 12 extended family members, we were planning on just our family and then everyone else just sort of horned in, I was really dreading waiting and dealing with this because a few were older in their seventies, and I knew or at least thought I knew that this would cause a severe strain or damper on the trip but it actually had it's benefits. My dh's grandma was in a wheelchair which basicly meant front of the line access to all the attractions and shows for our entire group, which makes me feel bad for benefiting out of her situation, but it was a little bit better for all of us.
Even though it may have seemed to you that you got front of the line access, in most lines people using wheelchairs and/or ECVs (motorized mobility scooters) wait in the same lines with everyone else. These are fully wheelchair accessible and are called "Mainstream Lines".
AK and the Studio were both built with all Mainstream Lines.
MK and Epcot are older parks, so when they were built, accessible lines were not common. As they renovated or added new attractions, they added Mainstream Lines as much as possible. There are a few attractions in both of those parks where the lines were not able to be made accessible. For those few, there is a wheelchair entrance. That doesn't mean there is no wait though. People have posted in the past that they got in faster in about 20-25% of attractions (but usually not much faster), almost exactly the same in about 50-60% of attractions and had to wait longer (sometimes much longer) in 20-25% of attractions.
Also, there are a few attractions where people with ECVs and wheelchairs can park in the front row for the show (Festival of the Lion King comes to mind). But, most of the the shows with wheelchair seating in the front have the majority of the accessible seating in the back. And many shows have wheelchair and ECV seating only in the very back row, including all the movies and audianimatronic shows except for Lion King.