Regarding the Rest Area Parking dilema...
I've parked 45 foot tour busses in the "Passenger Cars Only" section, I've parked 45 footer busses with trailers in the car section only...
Charter busses and private coaches...
Straight trucks, and 18 wheelers.
The thing I do is approach slowly to see how the truck section looks... if it looks full, chances are it probably is.
Sure, sometimes there's a golden spot open in the middle of the pack... but usually if they're parkin' all over on the approach, then there's no golden spot in the middle of the pack. Now, with a straight truck it's alot different, 'cause you're usually less than about 35 to 38 feet or so.
Therefore you can park much easier (usually) than a bus or 18 wheeler. In some rest area's you'll only gonna take up 2 spots if you angle it just right. Park along the fence towards the exit or on the exit ramp on the way out if there's room. Stop and walk it out though, throw the 4 way flashers on and walk it out -
I would recommend parking in the middle or up closer to the exit side of the rest area if you're gonna park.
Why? to be considerate towards other drivers that may be coming in behind you... who may or may not be doin' the same thing.
Also, if you're closer to the exit then you're less likely to have to struggle to get out, and/or get out of a parking space.
I would recommend parking in the rest area much more than parking on the shoulder.
The only exception to that would be parking on an entrance ramp, though some states have been known to chase you off of those too, like TN and SC.
Not sure where to park your straight truck... park it in the big truck section, or at a truckstop. Rest Area's are nice sometimes - but for a solo driver it can get dangerous at nite. I'd rather be at a truckstop or shoppin' center that's well lit all around me.
Leave your running/marker lights on at nite when you park... no matter where you park.
Well, I'm tired, I'm goin' to bed... drove from SLC, UT to Denver, had winds, and ice... then I got to Denver and thought I'd have 2 hours to sleep 'cause I was early - and they took the load early.
Soooo, now, I'm goin' to bed... along the fence at a crowded terminal.