Lexington what?
1) Don't get dropped off inside a city (unless you wanna explore). Get an exit guide & try to get let off in a high traffik area. (fast food, truck stop, hotel, ect...)
2) Don't jump the gun on bullshit rides to some unknow exit 3 miles down the road. Even if you've been waiting a while, if yr in a good spot, wait for a decent ride.
3) do yr best to stay OFF the interstate proper. Cops suck. nuf said. Most states don't mind you being on an on-ramp (digihitch is a good resource for state legislature)
4) If you run into homegaurds, don't go back to their camp if you have to overnight an on ramp. Find yr own spot.
5)Try not to get let off @ intersecting highways. Rest areas are also hit or miss. There's almost always a trooper on duty, and the groundskeepers are generally assholes. If yr ninja, with a little luck you can get good rides here. especially if you don't look too intimidating.
Most importantly: have fun, be safe, and get ready for a sunburn & hours of frustration.
oh, and be entertaining. A lot of times, if you tell a few jokes & stories/play into the wide eyed vagabond adventurer archtype, you may just get a few kickdowns.