Sounds good to me, gehajake!

How much power do you need at the lake? A big generator is MUCH cheaper than a 1/4 mile of electrical line. (You also then have a big generator available if a tornado hits your town and your house is without power for 30 days.)

A fixed dock that can reach one of your good fishing places is the most convenient way to get multiple disabled people into some fish catching. However all of the handicapped docks I have seen (only a few) have big railings between the fisherman and the water. Nobody wants that. I would probably make a dock with eyebolts in the deck and a strap to attach wheelchairs such that they cannot reach the edge. (Wheelchair seat belts must be worn at all times on the water and on slopes.)

I don't know if that "looks" demeaning (like toddlers on a "leash'), but I will call one of my wheelchair buddies. People that are only paraplegic could do a lot of fishing on their own if there weren't any obstacles in their way!

For amputees that can still walk, perhaps some boat seats on the dock? Then they can swivel and fish. After your event, just pull the chairs out of the plate and put them in your storage shed. The deck plates are almost flush mounts, so your kids could run around the dock the rest of the time. (Or you reinstall the chairs for the kids that are wigglers so they don't scare away the fish!)

Do you have any friends that are Boy Scout leaders? Building handicapped access where the scout has to organize the building project materials and secure the scout labor is guaranteed to be approved as an Eagle Project. If you build the dock, maybe the scouts could build the roof/sunshade over the dock? They could also make the trail to the dock wheelchair accessible.

Just throwing out some thoughts if you keep moving forward on that idea.