Before leaving -
Do as much internet scouting as I can. I think we all do that and all have our different way. Usually first is available huntable land. I don't need the MOST public land but I do like places I can stretch my legs a little and separate myself if need be. Next I'll obviously try and be sure there's turkeys in the area. I'll research a state's department of wildlife website and hope they have some statistics on bird densities or really anything that gives me clues as to where to concentrate my efforts. If all that is blank I'll call the local biologist with some "ideas" and ask his/her input. I've found you get a whole lot farther if you have already done some research and need answers on specifics rather than just asking "where should I hunt!?" Once the animal aspect is sorted out I'll look for high points to listen and areas where I "expect" gobblers to be and start pinning them.
Another thing I've really dove into lately is access points and public roads. In some states and sometimes even different public hunting areas within those states are different rules. Sometimes roads open after turkey season, sometimes may 1st, etc. it's important to know when those roads are open. It's also important to know the legality of where to park. Some places you HAVE to park at an access point. Other places you can park anywhere on the road. I like to have all the little things ironed out the best I can so I'm keeping the surprises to a minimum.
Once I'm there it's all about covering ground. Make sure I can put a real life look with what I imagined in my mind. Sometimes areas don't look as good as you thought and other places really pop when you get there. I'll pin those and do short walks trying to strike up birds, look for sign, see birds, etc. From there it's narrowing all that data into a few key areas I feel comfortable in and trying to zone in to kill a bird. Sometimes that comfortable feeling never comes and after a few days it's time to head to a different area. Then revert back to covering ground!