Hiking trip during marathon training

I’m heading out on a 2-week national parks road trip soon and will be hiking most of the days. I’m in the middle of Chicago marathon training (at around 45-48 mpw right now) and trying to figure out how to balance training during my trip. Realistically I don’t think I can get in the same number of miles so are there certain types of runs I should focus on? Could I use hiking as a replacement for my easy runs for those two weeks?

My biggest concern is losing any of the fitness and speed I’ve built up during training so far - any advice would be great!!