Some of my best memories are XC PCS trips Jax/Norfolk/Newport/Annapolis <> San Diego, Monterey, Long Beach, San Francisco. On leave, relaxed, going northern route in summer, southern route in winter, eating great pork in Iowa, Tex-Mex in TX, side trips to see friends or explore New Orleans or other cities...I fully admit I planned legs of trips so I could overnight at AFB's superior guest officer accommodations.
That said, DOD reimburses the official distance between current duty station and next duty station at official rate, allowing X miles per driving day for his allowed travel days.
Questions for him to ask:
- Will he be reimbursed the POV mileage rate if he is not driving the car?
- If he is, will that mean he would not be entitled to govt funded air trans?
In CONUS, military members are expected to drive their own cars. Or, if they don't have a car - perhaps they sold it, they elect to take the air trans.
If he itemizes his tax returns, he may (operative word, I'm no CPA) be able to deduct the auto transport service as an unreimbursed job-related moving expense.
This is all about entitlements under Joint Travel Regs (JTR) and what his orders specify.
If he is going sea duty>shore duty, he will get x days travel time (not charged as leave), y days proceed time (get stuff done admin time) and allowed z leave days, with a report NLT date to new duty station.
Military people are pretty creative, and Navy folk have been doing coast to coast PCS for years. There will be gouge and collective wisdom available from his shipmates.