I'm in the process of designing a custom frame (to be built this winter) which will be both my main XC ride as well as the workhorse for an extended (2+yrs?) bikepack adventure through Central/South America and beyond. If all goes as planned I'll be leaving in about a year... so I'll have a full season of regular riding and shorter training bikepack trips to get parts/setup dialed in.

My questions for y'all are
1) If you have a custom frame, what are the design elements that you really nailed?
2) What are some things that have come up that make you wish you had done it differently?
3) If you're running a stock frame, how would you like to change it to be better suited to bikepacking?

I've been a longtime reader here and have done a fair share of road/CX touring (longest trip was 3months overseas) but would love to hear some thoughtful ideas before the frame building begins.

The basics I'm pretty set on, but not opposed to making changes:
29er steel hardtail (built for 120mm FS)
3 bottle cages (triples for Anythings)
slider dropouts (will be running gears)
two sets of top tube cable guides- one set on top for full housing, one set underneath for 'normal' housing
rack/fender mounts (not really planning to use them, but want to have the option)

I'm currently riding a '09 carbon hardtail, which I love but wouldn't trust for the long haul.

Thanks in advance for any input!