This is easy. As long as your employer is picking up the tab, then do the following:
- Pick the airline that has the most flights to your home airport:
ATL/MSP/etc ..... pick Delta,
ORD/DEN/etc ..... pick United;
DFW/MIA/etc ..... pick American;
Others ..... Pick the airline that has the most checkin positions at your airport.
Stay with that airline whenever possible.
- Pick either Hilton, Marriott or Holiday Inn. No matter where you go, each will have a hotel nearby. Stay with that hotel chain whenever possible.
- Pick either Hertz, Avis or National/Alamo. No matter where you go, each will be available nearby.