A big day ahead of me. Yellowstone and Grand Teton. Two of the great National Parks. Again, scale takes some getting used to. The two parks together with the neighbouring state parks cover an enormous area, over 100 miles long. There was some trepidation; winters finish late round here and the forecast was cold. I didn't set off too early so at least it would warm up a bit. But it was still only 4deg when I set off at 9am.

I had my preconceptions about Yellowstone. Long queues of slow moving traffic, high prairie and geysers. As ever, I was mostly wrong. The scenery is so much more. Huge mountains, enormous lakes, epic valleys, great rivers. And traffic couldn't possibly be an issue, simply because it's so big.

The ride up to the park is dramatic enough, following a wide valley, watching the scenery grow around you. Once through the east gate, I had a realistic target; head to Yellowstone Lake in the centre and then head south and leave by the South Gate. This would only let me see a quarter of the Park but that's as much as can be achieved in one day. The road steadily climbed into snow and frozen lakes and once at the top, I was able to start seeing the main plateau laid out in front of me. In the middle was Yellowstone lake which has 110 miles of shoreline, so is pretty darned big!

The beaches along the lake were a nice spot to rest and I found one serving coffee which was much needed. The ride around the lake was lovely and took in waterfalls, swampy deltas, cliffs and wildlife. I saw moose and bison; eagles too. Photos not easy when riding a bike. But I was very lucky to see a bear not far from me during my lunch stop. Having established it was a black bear, I was able to watch it foraging around for a while. The information boards were quite clear about bears; black bears you can stay still and watch them. Brown bears (grizzlies) you get away from as fast as you can!

I then arrived at one of the geyser sites that you can walk through. Very strange place. A strong sulphur smell, hot moist air, quite a lot of noise (though a busload of Chinese tourists did their best to top that). Amazing to witness. The rangers delight in telling you that they are the essential valve for the caldera. This is the underground volcano on which much of central Yellowstone sits on top of. It's not just a volcano like we imagine them; it's 40 miles in diameter and the largest one known and if it did explode it would probably cause significant destruction to the planet, apparently.

Time to head south I thought. The route down away from the lake follows beautiful snow-white valleys and leads you into the Grand Teton National Park. A stunning range of mountains; 14,000ft peaks that you pass along the bottom of following the Snake River. They are certainly grand and very photogenic. The valley includes more lakes and plains and widens out as you progress back into classic Wyoming scenery.

It's then a short zip across this plain to Jackson, where the next set of mountains rise up. Jackson and Jackson Hole are major winter-sports destinations. Jackson is also very smart. It was strange after so much real America to suddenly find a slice of California up here. Smoothie bars, power walkers, silly dogs. This was very different. Nice town though. Bit pricey but lots to see and do.

Managed to find some tat shops and get some shopping done. My family are happy to let me go on these trips as long as I bring them back bag-fulls of tacky souvenirs. And I have to buy small as I’m limited by the luggage capacity on the bike.

Once I’d loaded up a few bags, I found a nice burger restaurant with tables on the upstairs balcony overlooking the comings and goings of downtown Jackson. I could live here I thought as I tucked into a most excellent burger.