If I travel by car and there's any space available at all I've got to have some sort of instrument to play. If it's a weekend and not too much baggage I'll throw in my old Yamaha FG-335. It's a beater but it sounds great and I love it. If we're packing for a week or so I'll take my little Ibanez Day Tripper. While the tone is kind of on the ukulele side it's at least SOME way to enjoy music in the beauty of the out doors. There's a pic below of it beside my Yamaha. For a few years I loved to bring my homemade cigar box guitar. It's got a piezo in it and I'd even throw in a little pignose amp to get some breakup slide going on. What do you guys throw in the car to satisfy your musical needs?