What time of year are you planning this. The good advisors will need this info I imagine. You can't do both Mtns in the same day for sure. Other than than that's all I can give. Both are great to visit. Both have great visitor centers. And if you can get into the lodge at Rainier, it's worth a trip. Love those mountains...

Unless they have cut thru a new road in the last year,Highway 504 dead ends at the coldwater visitor center. If thats the case, your other option would be taking 503 thru Cougar to the Windy Ridge lookout. Then on to Randle. You could stay in Randle or Packwood then take the east entrance to the park heading west to 706 then north on 7 to I-5.. You didnt say when you were going however,,this would only work before the snows hit.

I'd go back out to I-5 then back in to Rainier. Plenty of affordable places to stay near the freeway. After St. Helens you might find yourselves a bit volcanoed out anyway.

if you're still looking for a place to stay close to Mt. St. Helens, THE place to stay is Blue Heron Inn (blueheroninn.com). it is a bed and breakfast(and dinner...), new, very nice, not too expensive, and the owners have lived in that area forever... with breakfast, the owner will tell you his personal experience of when Mt. St. H erupted - fascinating! Highly recommended - just off I-5 at Castle Rock

Thanks for the tips. We are actually going to be there next week (mid-week), so snow closures should not be a concern.

After reading Rick's take, I double-checked my guide book (2002) and, after careful reading, it appears to suggest that the Coldwater/Johnson area on 504 and the Windy Ridge area on 12 are separate. There's no mention of a route between them. So, I guess the real question is then - Which side of Mt. St. Helens should we visit? If Windy Ridge (which is more remote) is preferred then we should probably drive around the back highways and stay in Randle, Packwood or Ashford. If Coldwater is better, then we should probably head back to I-5 and find someplace with easy access to Rainier's Nisqually Entrance. Thoughts? What hwy and town along I-5 are good to connect to hwy 706, keeping in mind we would be heading from the south?

Mel...it all depends on your interests..
If its just scenery. IMO the back way is more scenic,but no tourist facilities to speak of. 504 has the visitor centers which are very nice.

The Windy Ridge side is definitely more remote and less-traveled. Most tourists go on up to Coldwater Ridge because there are more facilities, a good view of the crater, and easier access from Interstate 5.

I much prefer the Windy Ridge side. As mentioned above, from I-5 you can take Route 503 east through Cougar, along the Lewis River. A very worthwhile side trip on Route 93 takes you to the Ape Cave lava tube, which you can explore for over a mile underground (bring a lantern & flashlight, or rent them at the cave). A bit further up the road is the Lahar viewpoint, where you can walk onto one of the 1980 mudflows and stare up at the mountain.

Continue back along 503 east to Route 25 north, which will take you up the east side of the mountain. After a long twisty road, you will eventually turn onto Route 99, the access road to Windy Ridge. This road takes you through the spectacular area of blown-down trees as you ascend onto the ridge. Check out the Harmony viewpoint for great views of Spirit Lake. You can hike down to the lake from this spot. Once you reach the Windy Ridge parking lot, it is a short steep climb to a great overlook onto St. Helens, Spirit Lake, and much of the devastated area.

If you continue back down 99 and then north on 25, you will end up in the town of Randle. There are some motels there, a bit further west on Route 12 in Morton, and a bit further east on Route 12 in Packwood.

I would suggest continuing the east side theme on Mt. Rainier, continuing west on Route 12, then north on Route 123. One option inside the National Park would be to turn west onto the Stevens Canyon Road and ascend onto Rainier's south shoulder at Paradise. This is a great road with wonderful views all along. One site that many miss is Box Canyon, a spectacular deep narrow notch cut into old lava flows. From Paradise, you can then continue westward, dropping along the Nisqually River along Route 706, then out to Tacoma and Seattle.

Another choice would be to go back down the Stevens Canyon Road, continue northward on 123, then turn onto Route 410 (west?) at Cayuse Pass. Not much further along, you can turn off onto the Sunrise Road, which ascends onto a really fine ridge immediately northeast of Rainier. I think the best views of the mountain can be had here, and there are great hiking trails too. Its not a very far walk to the front of Rainier's Emmons Glacier from the White River campground, which is situated below Sunrise.

From there, you can return to Seattle via Route 410 to Enumclae, then Route 169 to Renton.

Sorry if this is long-winded! I do this trip a lot and have strong opinions.

Rick and Alf: thanks for the info. Alf: not long-winded at all. Long, but full useful details that the guidebooks haven't told me. I think we will head to the east side of both mountains and stay in Packwood. Apparently the Visitor Center at Silver Lake is only 5 miles along 504, so we could always hit that, back-track to 5, and then take 12. Would this be a shorter trip than the 503 option? We will probably make decisions when we're there, depending on how much driving we want to do. At Rainier, if we wanted to see Paradise, and then Sunrise, how long a day would this be? Thanks again for the help.

Went and saw both Paradise and Sunrise last summer. Very easy to do. We didn't start until about 10am in Puyallup and were back there by 7 or so. Took a picnic lunch with us. It was well worth seeing both angles of the mountain.

It's beautiful, hope you have clear weather for the great views.