I saw the same words of caution when researching front racks for my mountain bikes...it's still worth looking into though as not everybody has that issue. Headlights and signals can get blocked too...depending on the bike and rack design.
Do you "tinker" with your bikes mechanically? What about partially disassembling for transport in truck bed (or anywhere else for that matter). Not a good option for a weekend, but for a 3 month stay maybe worth it?
Also...is your truck a long bed? You may be able to go across behind the cab with one of them?
'04 GMC Sierra 2500HD, CCSB, D/A, MaxBrake, B&W Companion, Retrax Pro, AR Power Steps
2013 Rockwood 8289WS w/Diamond pkg
1969 Camaro RS/SS Convertible
Dad's old 1968 Empi Imp (recently recovered from under 21 years worth of boxes/dust)