Totally!! 15s gets you big returns at many ultras! She might consider the 30mi option at the
SRT Run/Hike in September. It's a walk-fest for many, anyway. 15s got 12th place (of 30) last year. Just need to do them for 7.5 hours. ;) There
are appropriate joggy bits, I'm sure.
But, no pressure, and no rush.