Colorado, Wyoming, Montana, Idaho From April thru July.

trop-a-cal wrote:
Yep, we spent a week in Wyoming one day in April, as all passes were closed when we got out of Yellowstone, and so was the only gas station. We were on E but lucky me I had a gallon and a half in a container and needed it all to get to the next station. Summer must be about a month long up there.

On Wyoroad nfo it lists which passes are closed. Some of the main road passes like South Pass are open much of the time. South Pass is the main route from southern to northern WY from Rock Springs, Farson, and Lander.

We never make reservations. When traveling around the state, we will call an RV park we find in the Woodalls Directory a couple hours before we plan to stop, and make sure there is a spot for us.
If you want to use State Parks or Forest Service campgrounds, most of them do not accept reservations. More often than not, the contact number will be a Ranger Station several miles from the campground, and nobody there has any idea what the current status of the campground is.
Another thing to be aware of is that very few of the State Parks or Forest Service campgrounds have any dump stations. If you use a "blue tote", be sure there is a place to dump it BEFORE you fill it! There will often be one vault toilet and one water faucet for each 5 or so campsites. There will be no lights and no electric power available. There will probably be no bath house or showers. There may or may not be paved interior roads and sites. Be sure to read the rules posted on the entrance signboard. Dumping your waste water in the vault toilets is often forbidden, but some places do allow it.
Please, be VERY careful with fires. Pay close attention to the posted fire dangers and fire restrictions.
Let me know if you get close to Billings.

Yep, we spent a week in Wyoming one day in April, as all passes were closed when we got out of Yellowstone, and so was the only gas station. We were on E but lucky me I had a gallon and a half in a container and needed it all to get to the next station. Summer must be about a month long up there.

GoPackGo wrote:
Yup, been in Wyoming in early June. It is NOT summer there at that time of year - at least not like June is in the Midwest, where I'm from. April/May could be interesting.

We're about 15 miles north of Cody.at 5000 ft. We get our last freeze about 1st week of June. A little cooler in Yellowstone. You will see the most wild life at this time.Although nights may freeze the days are comfortable.

Only time reservations maybe needed would be around major holidays. Memorial Day and Fourth of July. We normally find a place and hold up over long holiday weekends.

Yup, been in Wyoming in early June. It is NOT summer there at that time of year - at least not like June is in the Midwest, where I'm from. April/May could be interesting.

That is about what we did last year in the same time period. For weather reasons you might want to do it anticlockwise. April still has those whirly things & thunderstorms roaming around the middle of the country so a stop in New Orleans & then NW through Amarillo to Colorado may be a thought.

Reservations??? What are they? Only if you plan to be in a high demand area on a weekend. Most SPs seem to hold nonreservable sites for walkins. The trick is to arrive Thursday or early Friday, before the locals show up, & stay put till Sunday. We were at Grand Teton NP for 4/7 holiday last year. No reservations at Gros Ventre CG. Arrived 2/7. No problem.

Hang loose. You are not one of those vacationers trying to cram a months worth of travel into 2 weeks. Get where you are going early & watch everybody else scramble.

You'll be fine, maybe not the best camping spots but there will be spots. If you get to the coastal areas you might have some problem in July and Aug.
Just a side note, I almost always have snow on the ground till May.

I would not call CO, WY, ID and MT the Northwest, that usually means Washington and Oregon. The region you are going to is the Rockies and the Inter Mountain area.

That nitpick aside, you should not have any problems with two exceptions: big popular National Parks: Yellowstone, Rocky Mountains NP and Glacier NP. Best to has reservations for those. And the other problem period is national holidays: the Fourth of July mainly. CG tend to fill up then too. And Memorial Day if you are starting in April.

Otherwise you should be fine, we usually call ahead when we are a couple of hours out and get a campsite. And rarely have a problem.

BK+