Welcome Queue. Glad you've decided to register and join the fun here.
Know what you mean about gas prices.
Branches are OK. Just wouldn't use tiny ones that are almost all bark. If these are trimmings from a tree, they need to be seasoned before you use them. Using green wood can cause a cresoate build up in your CG.
Use any seasoned (dry) wood that you have available to season your CG. I used hickory chunks for mine with good results. The bonus for doing this is you'll have more of the special woods, like pecan, for smoking.
See if the source of the pecan will hold it for you until you can combine more than one purpose for the trip. If it is green, split and stack so it has good ventilation in a dry location. Don't put it on concrete or lay it on the ground. In a few months you'll have some mighty fine wood for smoking.
Hope this helps. Enjoy your CG!