Wired direct is the best way to prevent multiple boot-up issues. No problem if you leave it on, it draws very little. Battery will be charged when you return from your trip, no worries. Done this for 3 years on 3 different bikes.
However, invest in some preventative maintenance. Put some liquid (spray) contact cleaner with lube on the cradle pins and work them up and down to get the stuff down past the pins. They do corrode, so do this a couple of times per year. Take the battery out, clean/lube it also and the contacts, it will prevent that occasional "won't power up, gotta remove and reinstall the battery" issue.
If you find some of the buttons "stick" (stay yellow) at the bottom of the touch screen, chances are there is a build-up of fine dirt or a piece of grit between the front cover and the screen (you won't be able to see it). Using a T-6 torx, remove the 8 screws on the back, top cover, and carefully remove the front cover so you don't unplug the ribbons from the main board (no problem if you do, just a pain to reinstall, might need 3 hands). Conectors have locking bars. Remove 4 phillips screws from back of screen. Clean with lens cleaner or isopropanol and Q-tip, reassemble. IF that don't work, order a replacement digitizer on ebay. Or if you like spending $150, send it to Garmin for a refurbed unit.