I would presume this would apply but..I used to be a horrendous chipper. That 10 yard chip might leave me an 8 yard chip or a 30 yard chip and once in a blue moon might be on the green...then I stumbled across Phil Mickelson's short game video, watched it, worked at it, watched it, worked at it, rinse, repeat multiple times, and now feel like a reasonable chipper. I am not confused into thinking I am "good" but I reliably am on the green, will be in one-putt range anywhere from no to 4 or 5 times a round depending on the day, distance, and lies I had to work on and it feels like I chip one in every 8 to 10 rounds.
But that feels like the exception...his approach is VERY fundamental and it definitely applied to me...my lessons were all full swing, it was a glaring weakness in my game that now feels like a strength...but if I understand your comment correctly, you are saying this is the one time to pay attention to those type videos?
although, on rare occasions, that can result in a better location. We were playing a Chapman saturday and had this exact thing...ball on cart path, nearest point of relief no closer to hole actually moved us out from behind a tree. Huzzah for small breaks!
Since you said 3 months. I went with the approach of golf course density. No clue if most of them are private or not, but i might be a starting place to check.
Golf courses per square mile | Golf Channel
Definitely the NE United States has a lot of golf courses near each other. Stay in a city of Hartford, CT and you would be able to be with in 2 hour drive of golf courses in three of those states.
First thing is get a rule book, read it and definitely keep it in your bag. You don't want to face issues with penalty shots or a DQ for accidentally violating a rule.
In terms of how you approach the game, it depends on your personality. Some people play better under pressure and others prefer a more calm environment. Depending on what you are like, plan to play accordingly. For example, you can choose to keep score and know your position at all times or just write it down and ignore it till you tally it up after 18 holes.
Definitely practice as much as you can before the tournament, but don't try to make swing changes between now and then. Also, try to figure out where you are gaining and more importantly losing strokes. Then plan your practice sessions accordingly. You definitely want to strengthen your good points and focus on minimising the damage your bad points cause.
Finally, definitely ensure you are warmed up on the day before you tee off. You don't want to take a couple of holes to warm up and find your rhythm. Losing strokes aimlessly isn't good, especially in a competitive tournament
One other club I would suggest, especially if you can try it before you buy, is a mini driver. You will get these clubs in around 15* of loft, and this is smaller than a driver but bigger than a 3 wood. My friend uses one and finds it easier to hit off the turf. Plus the shorter shaft means he has more control than the 10* driver he has almost stopped using.