Average mileages are dependent on the person and vary.

Given that you already know what you've done in 6-7 day trips, I'd extend something similar to longer trips unless you know something more like you've been pushing extra hard and ended up exhausted. On my own trips, I do somewhat similar mileages in the month-long trips but then I'm also making sure I keep riding at a pace that I can sustain repeatedly - even for a one-week trip.