Hume and Crest are both nice rides, not too hilly. Is an extra 5 miles.
55 to Zula is a good idea. I just like getting off 55 and going through Rectortown.
I'd forgotten about Foxcroft. That would avoid both the big hill on St Louis and the rollers on Snickersville.
FYI - Custis Trail comes in at milepost 4