I agree with others that have said to reduce the mileage. I remember being in tip-top shape back in the mid 90s (I used to be a cyclist and race both road and mountain bike races), never having hiked before, and I asked a guy to give me the hardest 25 mile section near Lynchburg to do over a weekend. Well, he gave me the section that includes Three Ridges and the Priest. I gotta say I went into that thing thinking I was a bad arse, and after the first day of 13 miles I think I got my arse handed to me. So yeah, being in good physical condition is great, but I wouldn't trying going for that many miles your first time out. How about just doing the Smokies for example? That's 73.6 miles if you go in at Fontana Dam, and exit at Waterville School Rd. (you can park at Standing Bear Hostel). Just a thought...I think you'd have a lot more fun.