The Guardian is launching the fourth of its crowd-sourced, interactive road trips through the US on Monday 22 July.

I'll be covering my 1,000-odd mile route between Las Vegas, Nevada and Denver, Colorado in a rented car, sharing the driving with my friend Andy, and will be guided by your tips on accommodation, food, routes, sights to see and things to do – in fact, in virtually every respect other than personal hygiene, I shall submit my will to yours, dear readers.

In return, I will be tweeting updates from along the route, asking for advice, and sharing reflections on this magnificent stretch of the US. I hope that together we'll be able to unlock some unusual experiences, barrel down empty desert highways, have dreams of riches on slot machines, visit ghost towns, and conjure up the spirits of the west.

Virtually none of the trip is pre-planned. We have a starting-point – Las Vegas – and an end-point – Denver. Everything else is up for grabs. So please send along any suggestions you have for the itinerary, our objectives, music, snacks, and even the name of our expedition.

As things stand, we'll be starting and spending a good chunk of the first day in Las Vegas. I've visited the city once before and stayed a couple of nights in a hotel that looked like a Lego castle. Where should I go this time? What are the must-sees? Should we be revelling in kitsch and gambling, or challenging our preconceptions about the city?

We'll be travelling with a photographer, the very talented Jacob Kepler, who is based in Las Vegas. Can you surprise him in his own backyard?

The next stretch will lead us north-east out of Nevada and into Utah. How do we take in the diversity of this great state? Should we go to the Shakespeare festival in St George, or plunge into its national parks, or both, or neither? And, of course, Utah is the spiritual and cultural centre of Mormonism. Where do we go, how do we begin to understand that?

We'll be crossing into Colorado for the final leg of our journey. I'm American – my dad is from Medford, Massachusetts – but this part of the US is terra incognita to me. Both Utah and Colorado have a reputation for epic landscapes. What are the best places to see them? Help free us from the blandness of the interstate and peer into the nooks and corners of the country.

Our crew is brave and game for anything. We will accept any reasonable challenge, we are happy to drive long and far, but it may help to know that we especially love spicy food, outdoor swimming, friendly people, good coffee, independent bookshops, wide open landscapes, unspoilt nature, roadside Americana, tumbleweed, iconic motels, giant balls of string, pre-Columbian history, and pleasant surprises.

Tweet me – if I'm not there, try @GuardianTravel or @GuardianUS, or GuardianWitness – or leave your tip in the comments below … We await our orders.

Marcel Theroux is a travel writer and author

• For more information on holidays in the USA, visit DiscoverAmerica.com