There is nothing special about 2,500 miles. You shouldn’t need to to anything special to the car unless you have been deferring needed maintenance. An oil change and a clean air filter would be good, but you don’t even need a new filter if you changed it less than 20K miles ago. Before your trip make sure you have your tires at the correct pressure, often about 32 lbs for many cars. If your tread depth is below 3 32nds on a tire it might be good to get a new one. So, up to date on maintenance, tires have OK tread, tires are at the correct pressure, there is fluid in the coolant overflow tank (about 1/4 full when cold), and you checked the oil level and it between the full and need to add marks on the dipstick. Good to go. I like to carry a quart of oil and check the oil level every morning and once a day (at a rest stop) during the trip. If you need to top off the oil you are all set to do that without spending $5.00 or more a quart a quickie mart.