While I do not work for Farmers, it has been my experience that they do allow exclusions. Usually, you will need to call your agent or a customer service representation at their call sent and request an exclusion form.
Although I am not a Farmers insurance agent, my understanding of Farmer's Roadside Assistance program is you can either call their roadside service while your vehicle is inoperable and they will tow you up to $150 or you can be reimbursed for your troubles. However, this is all dependent on having towing and roadside on your policy.
Roadside assistance varies by insurance company. From my understanding, most towing and roadside assistance coverage offered as part of an auto policy either has a set dollar amount to cover a tow, covers towing up to 15 miles from your breakdown, or covers towing to the nearest repair facility.
Even if you don't have a US driver license, you should still be able to find coverage with most insurance companies. You mentioned that you will be traveling around the US so it's important to note that US insurance companies require a "permanent" address before they will issue a policy.