Claus Clausen, of Des Peres Travel has retired and he and Des Peres Travel are no longer providing travel arrangements for US riders bound for PBP. In their place, TravelHaus of St. Louis has stepped up. The preliminary web pages for their offerings can be found here: https://www.pbp19.com.
It is hoped that all of the services available in 2015 to US riders bound for PBP will be offered again in 2019, including airfare from numerous US cities, airport transfers to hotels, lodging in SQY and a limited number of intermediate control towns, and bag drop services between SQY and some control towns.
Update (June 21st, 2019): It appears that this travel agent is dropping its original offering of charter flights from some cities, and any airport/hotel transfer transportation. Further, despite repeated requests, the vendor will not be offering drop bag service in Rambouillet.