Hi!
I don't have much success hand quilting in a moving vehicle. I just can't get my stitches to go where I want them to go. It's just too bumpy for me. I prefer to do a binding...or some hand piecing where the stitches won't show.
I don't spray baste anything I'm going to be hand sewing. I think it would make it harder to stitch through....but since I've never tried it, I'm only guessing here.
For travel I prefer a smaller hoop, 9-12". That again is strictly for space reasons.
As for the needles/threads questions...you'll probably get different answers from everyone that answers. It truly is a personal preference. I like #10 needles, John James gold eye are great! As for thread, I am a complete Mettler junkie! I like their threads, they don't break or fray. I also use thread heaven conditioner on the thread instead of beeswax. It comes in a tiny blue square, easy to use, easy to store. I find it lasts longer for me than the beeswax did (again it all comes down to personal preference!)
When I'm traveling I like to keep everything together in either a zippered craft bag, or a plastic tote. Be sure to put any pins you have in a sm. ziploc bag, even if they are in a snap shut type box....ask me how I know!!
I also like to use liquid skin on my underneath finger. A couple of good coats on your finger will help minimize the pokes with the needle. (another draw back to quilting while driving...IMHO!)
Have fun!!
Gail