Food costs are an estimate and are higher in the winter because I am more likely to eat at a restaurant than I am in the summer when camping. Camping can also be brought down to $0 by staying at one of the free sites, but that means no showers. (I always feel bad for my fellow Metro-North passengers on the way home.) And before you ask, yes, yes, yes, I've done price comparisons with Zipcar as well as renting a car in Manhattan rather than Poughkeepsie, and they are both more expensive.
Going for a few more days becomes more efficient by dint of spreading the Metro-North fare out. Even more efficient is traveling up with friends who can split some costs.
By the time I finish my Catskills 3500 patch, it will be the most expensive patch on my blanket, I think. Given that I've done some peaks in pairs (even six in one day), plus some where I didn't rent a car, let's say it's $100/peak for 39 peaks. That's about $4,000!
And maybe now that I look at this, I won't go up in March as I had planned. All my necessary winter peaks are done, and it's $100 cheaper in summer than winter. Right now I'm saving money because I may have some big expenses coming up, and it's probably not fiscally wise.