So I privately emailed David about switching my Long Run for a Long Hike before I realized there was a forum to post this stuff too. Anyway, for full transparency I have attached the correspondence in case anybody has a similar question or anything else to add.
Me: In two weekends from now, I have a recovery run followed by a long run (29k). This is also a weekend that I have a long hike planned (22km). I am debating whether or not I should replace the long run with the hike, or should I try and shift the long run to be early in the following week? I fear shifting the long run so that I have two long runs in one week may be too much training load but I would like to get your opinion.
David: This is a tough one. Is it possible to extend your hike from 22 to 29km? That would be my first recommendation.
If not, yes, move the long run to mid-week and take the next 2-3 days off until your hike, as the hike will make up for the mid-week volume.