DH and I are planning a Sept 2018 trip to these parks. New for us. We want to enjoy the sites - natural beauty of that area, and wildlife; take some easy walks/hikes. We're flying into Billings on 9/9 and spending the nite there, as we have a late arrival; will be departing from there on 9/17 (staying there again for early a.m. flight on the 17th). Yes, it's short, but that's all we want for our first trip.
We plan to take the Beartooth Highway into the park, and then exit via Cody and Rt 72.

With just 6 nites, we're trying to decide how many to spend in each park. We've made reservations for 3 nights at Canyon Lodge, and 1 nite at OF Lodge (also considering changing that nite for lodging in W.Yellowstone. But that leaves us with only 2 nites in GT.

First question: should we stay only 2 nites at Canyon and then 1 nite at OFL and 3 in GT? Or some other combination?
Second question: It looks as though we'll be retracing our route on 9/16 to get back to Billings. Or are there other routes we should take?

Appreciate the advice.

I wouldn't cut down your time in Yellowstone--it's huge and there's lots to see. I think a day or 2 in GT is fine--beautiful, but less to see/do compared to Yellowstone.

Yellowstone is 7 times bigger than Grand Tetons. Your ratio of nights in each park is perfect.

I agree with those above, spending the bulk of your time at the YNP lodges. Can you add a night at one of the Mammoth accommodations? I loved it there. These are my blog posts on Mammoth:
http://www.travelgumbo.com/blog/yell...th-hot-springs
http://www.travelgumbo.com/blog/a-ye...mmoth-terraces

Keep in mind that September is the end of the summer season at Yellowstone. It was when I was there in 2016 and, with snow coming to the roads over the higher passes, some were closing intermittently and altogether late in the month. Keep an eye on it in case you need to divert on your return drive to Billings.

I think the 4/2 split is good too. You can't count on the Beartooth being open if a storm hits in September. Sometimes there are problems going over Sylvan Pass to/from Cody as well but it's not as high as the Beartooth. The north entrance at Gardiner is the lowest elevation one. Have a back up plan for entering/exiting through the northeast and east entrances in September. I wouldn't swap the Old Faithful night for West Yellowstone. We really like Signal Mountain Lodge if you're looking for a place in GTNP.

It depends on what you are into. If its just for sightseeing, then two nights at Grand Teton are more that enough. Sightseeing at Grand Teton basically consists of different views of the Grand Tetons from various viewpoints and looking for wildlife. On the other hand, if you are avid hikers, then you might want to spend more time at Grand Teton. Four days in Yellowstone is in most cases enough to see most of the highlights of the park, but not an in-depth visit.

If your flights are not booked, one thing you could do is to fly into Billings and fly out of Jackson Hole which will prevent you from having to retrace your trip back to Billings, and may be buy you an extra day by avoiding the travel back. Depending on the airline, the cost may not necessarily be different. A hypothetical trip with your dates on Delta out of Minneapolis costs the same for both options.

We crossed the Beartooth and then spent a week in Yellowstone last August. We were not ready to leave.

I also think your basic plan is good, and that you should not leave the Park for West Yellowstone. If anything spend a night in Mammoth, as suggested by MmePerdu, or the Lake Hotel.

Regarding your second question, I'm not sure what route you are looking at but it seems like there is only minimal backtracking on your route. Since you are returning to Billings it's mostly unavoidable. If you could make it a linear trip that would help of course, but rental car drop off costs may be quite a lot.

Good luck.

Thank you all for your suggestions and cautions - about road closures due to snow. We'll look at Mammoth - perhaps trade one night at Canyon for that area. And check out Signal Mtn Lodge.

Bookmarking thanks.