I´m trying to work on a budget for such a trip. We´d like to stay in various types of accomodation but nothing too fancy. A couple of nicer motels/bed & breakfasts
Budget is my big issue now too. I'd figured up what I thought we'd need, and I actually had it in the bank in my vacation account . . . then I spent it all (well, I kept a little more than $1000) rather than finance my new car. It was a sensible decision: Why should I pay interest for a car that I need NOW (and a car I'm going to need for this cross-country driving trip) while holding onto a good amount of money that I won't need for 1-2 more years? Still, it made me sad to spend that money that I'd saved specifically for the cross-country trip.
We're planning to use inexpensive hotels for our trip. We love camping, but it doesn't seem to be a good choice for our trip plans. We'll drive my Honda (for the gas mileage), but it doesn't have space to carry a tent and sleeping bags; plus we don't want to come back to a hot tent at the end of a day, nor do we want to spend time pitching and striking the tent every day. Originally we'd planned to rent an RV (we have no interest in owning one), but when we looked at the cost of renting + reduced gas mileage, we found that it just wasn't a good choice for us. My husband travels for business fairly frequently, and he's building up "free nights" at Marriott, Holiday Inn, and Country Inns & Suites. Normally we'd use these freebies for long-weekend getaways, but now we're saving them up for our big trip. We're also going to do a couple of those get-this-hotel-credit-card-get-one-night-free deals. My hope is that we can get HALF our nights for free. We've had excellent luck with Priceline hotels in the past, so we'll start there; for example, we "won" the JW Mariott in New Orleans for $60/night during spring break -- that's less than half price! And then there are some places where we know we'll pay a premium price; for example, we know we want to stay inside the National Parks at the Grand Canyon and the Grand Tetons -- we'll just bite the bullet and pay those big-bucks prices. We're hoping that our paid nights can
average $100/night. We're also "easy" in that we're a family of four; we fit into a standard hotel room.
Food, of course, is going to add up -- and we're the type of people who, if we don't get good meals, get grouchy. We'd burn out on a menu of all-sandwiches-from-the-cooler. When we travel, we usually stay in a hotel that offers free breakfast, then we have one sit-down meal and one fast-food meal per day; then we always have healthy snacks and drinks in a cooler. For a month-long vacation, we simply cannot pay hotel prices for sodas, etc.! Often we split two meals between the four of us, especially if we're getting take-out. I'm thinking we'll budget $100/day for food (two teenaged girls -- does that sound realistic?), which will include grocery trips every couple days. We're also saving up our Discover Card points and will use them for food gift certificates when the trip's closer.
I'm nervous about gas prices, but my car gets 40 MPG on the highway. Of course, we're sacraficing space for gas mileage, so we'll have to pack lightly and plan to wash clothes every couple days (this is what I'd have done anyway). We're small people, so this isn't a big deal. My map computer program says that @ $3/gallon we'll use around $600 in gas for the trip we've mapped out. Of course, that doesn't include driving-around-town gas, so we've put double that amount into the budget. DH bought me a Garmin directional thing for my car at Christmas (I love it and can't wait to go somewhere out of town!), so we should signfiicantly cut back on our usual getting-lost miles.
National parks -- buying a family pass is a no-brainer. I think the cost has gone up to about $75, but it admits everyone in your car into all the national parks you can visit for one year. Since admission is around $20/car normally, this will be a great bargain.
Souveniers -- as a rule, we don't buy souveniers. On a trip like this, we'll probably get a few things along the way, and DH had a good idea: If we pick up things that are cumbersome in the car, we'll mail them back to his office, where they'll wait safely on his desk until we return.
I'd love to hear specifics on what other people are planning.
Looking back, I think they were crazy but we had a GREAT time and I saw a huge chunk of the U.S.
Can I come along? 
