Are you planning to bag all the 4000ers between Saddleback and the Bigelows? I just finished a similar trip on Saturday. I started north of the Bigelows at East Flagstaff Road and continued south over 10 high peaks, reaching Maine-4 after about 56 miles of hiking over 4 days + 3 nights. I stuck to the Appalachian Trail, its side paths, and the herd path from S Crocker to Redington to S Crocker. I had someone pick me up at the end and drive me back to the car, otherwise it would have been a 40 mile roadwalk. It was an awesome hike with near perfect weather, expansive views of hills and lakes, and cool people (sorry I missed a certain fellow VFTTer on S Crocker by two hours). Only wish I knew the answer to all the thruhikers asking each other which mountain on the horizon was Katahdin.
The trip could be shortened by ascending Saddleback via the ski trails instead of the AT and by descending the Bigelows via the Firewarden's Trail omitting Little Bigelow. Other than that, there's little to shorten the trip unless you omit Redington or Abraham. If you're not an AT purist, once you get to Caribou Valley Road, you can do Redington, then head straight to S Crocker, skipping the AT up S Crocker. This would make it very tough 3 days + 2 nights.
How did you plan to get back to your car? You'd be getting out late on the last day and traffic is pretty light in those parts (if you're hitching). Only 11 hours of sunlight daily too.
You can tell the family you won't be alone. It's the AT and it's pretty crowded: 10-15 people every day. More on the weekends.
If you have any questions, I'm no expert, but my trip is fresh in my mind.
Steve