Crawl Space Foundation for Mobile Home

Need a foundation for a small HUD home. It's going to be an ADU on my existing property. I am contemplating two possible locations (see attachment). About 40' X 16'. I would rather not have a permanent foundation, but the project is within city limits of Helena MT. I'm looking for a minimum of concrete use while still complying with IRC. Creative solutions are welcome.

Key Requirements:
- Meets IRC and/or City of Helena Code