They must have improved the ramp since I lived out there.  There was a dropoff of a couple of feet when the water was low in winter and early spring.  There was no way that a boat the size of yours could have gotten in and out.
Donner is a beautiful lake for sure.  I always had trouble getting the macks to hit anything there.  I could see them come up off the bottom to look a plug or a flasher only to turn away and go back down.  Always did better at Stampede and Tahoe. 
Can you tell me what they were hitting?  I used spoons, flatfish, and Lymans and only got a few macks over the years.  Some years there were a lot of kokanee in August, but most years they were small.