Sorry about my wrong terminology, thank you for the corrections, I am revising my question a little so hope it is a little clearer. Thank once again.
We plan to travel to the US (Colorado) from the UK in early February 2018 under the VWP. Our return flight to the UK is scheduled for mid-June 2018. We plan to purchase an RV and then spend 60 days in the Western US then travel overland into Canada for approximately 40 days (asking US immigration to log us out when we leave). We understand our 90-day allowance will continue to 'run down' whilst we are in Canada. Our questions are:
Will our initial 90-day allowance expire when we are 'logged out' by US immigration. If not, does it matter? If our entry into the US expires whilst we are in Canada, is there any process for a UK citizen to apply for some sort of visa that would guarantee entry into the US for another 25 days or so?
After spending approximately 40 days in Canada (therefore 100 days after we originally entered the US), will we be able to simply apply for re-entry into the US at an overland crossing from Canada (and will the initial VWP entry in February have any bearing)? We will then spend approximately 25 more days in the US, heading back to Colorado to sell the RV and fly back to UK around mid June 2018.
While I understand that the B2 visa option would solve this issue, getting that process completed (timescale, interview in London, etc) makes it impractical for us in this case.