Over moderate terrain you can look to get about three miles an hour with a fully loaded pack. Cut that down to between a mile and a half and two miles per hour over rough terrain. Then factor in breaks. Yeah even when you're hopped up, with thirty five miles to go, you are gonna wanna stop for a while. Remember if things are bad enough there is a high probability of needing to fight either along the way, or once you get home. If you beat feet the entire way home and are spent when you get there, you're pretty much worthless if something bad happens.
Edited to add.
Packing a well thought out bag is all well and good. But never carrying it until you have to is a very bad idea. Once you get your pack made take a weekend and see just how realistic it is for you to hump it thirty five miles. I recommended this to a friend of mine, and when he finally tried it he realized that packing a shotgun and two hundred shells was a very bad idea. He'd always figured that a shotgun was exactly what he wanted in a SHTF scenario. He changed his mind and bought a rifle, and also modified what he carried in his GHB.
Edited to add.
Packing a well thought out bag is all well and good. But never carrying it until you have to is a very bad idea. Once you get your pack made take a weekend and see just how realistic it is for you to hump it thirty five miles. I recommended this to a friend of mine, and when he finally tried it he realized that packing a shotgun and two hundred shells was a very bad idea. He'd always figured that a shotgun was exactly what he wanted in a SHTF scenario. He changed his mind and bought a rifle, and also modified what he carried in his GHB.