You can always check to the local airport and get weather information from either an AWOS or ASOS, even density altitude. Most airports have a local phone you can dial. Just google the airport identifier closest to the track and get all the information.

i.e Shreveport, LA Airport = SHV

Google: AIRNAV + SHV

http://www.airnav.com/airport/SHV

Scroll down to Airport Communications and call 318-636-5757 usually a recorded weather message - if not, just ask for Air temp, Dew Point and an Altimeter reading. Then, along with the track elevation, you can go here http://wahiduddin.net/calc/calc_da.htm

Plug in the numbers and discover your density altitude (easier then buying and learning an E6B flight computer)