Bill, that route makes the most sense to me...otherwise, you gotta go way out of your way up 71. You can take 250 up out of ashland, but I wouldn't with a monty I don't think.
John, from chi-town 80/90 to the exit for ohio53N, take that to the merge with route 2East, take that to the exit ohio101...camp sandusky is right off the exit about a block.
From MI, I guess you could come down 75-280-51-579-2East (please verify these routes, been awhile) take exit oh101...OR just come down to 80/90 and follow above directions from chi-town. You'd be suprised how it's not much longer, not rural roads, but tolls.
Food for thought....hope this helps.