The best resource is the posted Serum Run handbook. Print it out and read it as it is chock full of good stuff. The only thing I recall shipping back in a return poly bag was used dog booties. Basically, mushers will use over 50 booties a day and some will have plenty of life left in them after the shorter runs. I had bought these $5 and $10 stamps for that purpose. You will note that an extra drop bag and an address card is referenced on the Serum Run materials for sending things back. Be aware that unless you have GCI as a carrier it is unlikely your cell phone will work in the village. You can use a Garmin Inreach or spot device (more limited) to communicate if you need to do so.

On the deposit issue, I think it is reasonable to expect that places will require a deposit. The group has 17 people and that will pose some wear and tear on infrastructure. And, I do not disagree with Robert about it being “skin in the game.”