a few things you can do

1) buy a float charger from harborfreight. sometimes it's merely $5, or $10 otherwise. clip it onto the terminals of the battery and plug the adapter to the wall outlet.
2) nice to have - go buy a small bottle of fuel stabilizer from an auto parts store, pour it into your fuel tank, then fill it up to the neck. do this before you are leaving.

that's it. enjoy your trip. when you come back, just start up and go. all will be good.