Schools S applied to were all on the East Coast but for one. We live in CA. All the estimates were just BS stabs in the dark that didn’t relate to our situation. So for travel expenses, I just created my own spreadsheet and assigned a O/W price per segment based upon whether the trip was nonstop to a major city or a connecting flight to a secondary market, then multiplied that by # of trips per year. That gave me a good idea of where we were going to stand at each school when the acceptances came in. For the one school in CA, I did mileage calcs and added a couple extra trips home, plus parking expense at school.
One thing I didn’t calculate per se, which GMT mentioned is the number of times that the parents go (or plan to go) and how many parents each time. We are spending quite a bit to get him there in the Fall (of course, it’s first one off to college, so we both have to go, and stay for the orientation). But figure in parents weekends, any other events you want to attend, and whether for whatever reason they need your help coming and going for any of the trips.