Wear compression socks and eat as much salt and drink as much water as you can. It's gonna suck, but that will at least make it survivable. My legs always get super swollen and I get really dizzy if I don't do these. You'll probably have to lay down with your legs up above your head to deal with the swelling when get there. That's all the tips I got. Have fun!

I simply think that you are very brave. I'm chicken to adventure into any outing where i might have to sit upright for more than an hour, nor walk more than a few hundred feet, etc, etc, etc. So funny, just 4 years ago, i was walking 2 miles during lunch alone. Keep it up.