The bad news is six weeks may just be long enough to lose muscle condition. The good news is that three days is not enough to gain any conditioning! (That's not totally true, but a body-builder friend happened to mention that six weeks is the time it takes to notice any change in muscle shape, mass, strength, so I'm extrapolating from that.)

But you will gain some experience on the bike, and that will be fun and valuable no matter what. It'll be a good shakedown, and you'll find out if your shoes, saddle, handlebars, etc fit you for multiple days on the bike, and you have a good chance to fix problems. You can dial in your packs, maybe leave behind stuff you didn't need before you start the climbing.

It's hard to do anything to prepare for the hills in VA--take them as they come. If as your name suggests you've done some backpacking in those hills, you're already somewhat prepared, at least mentally. I love the local saying, "Our mountains may not be very high, but our valleys sure are deep."

Have fun, stay safe, and good luck!