Reward tickets, lounges and car service question

Ok.

My family are travelling on airmiles tickets with BA from LGW to MCO and thus my dates are fixed. I didnt have enough airmiles to fund all 4 of us so I will be using VA miles to get myself to the land of the mouse. I want to burn my VA miles in an utterly selfish manner by getting a one time, one way shot in Upper combined with an already booked one-way econ reward return flight from MCO to LGW. I have 63,000 left

I simply cannot get a Upper flight to MCO on miles. I accept that and am now moving on n(

What I have found is that there are upper miles flights to JFK, BOS, EWR, IAD and MIA available on the same day! What my current thought is, is for me to get one of those flights and then use either my continental miles or Ba miles (for AA flight) to get an internal reward flight back to MCO. (I already have a VA econ one-way return booked for the MCO to LGW homeward part)

So to my questions. I live in EDI and will be flying down the night before on the BA shuttle to LGW to stay at the hilton. If I part with the extra miles to get the car service rather than using the national express bus, will it pick me up from gatwick and take me to heathrow? Is that allowed as its not a residence or office?

Are there any arrival lounges at any of the USA airports that I could use based upon arriving in Upper? This would help sway my decision as to what airport to fly into (The onward flight will be a separate reward flight in economy.)

Thanks

Not sure about the CDC from LGW to LHR but can't see why not - it's within the 75 mile free distance [though some people think that's not a good use of miles but they are YOUR miles to burn]

There are NO VS arrival lounge in the US so that won't affect your routing decision.

Hi

Many of the US Airline Clubs allow purchase of a "day pass" (ie Admitals Club, RCC etc). We have done this a few times.... No Clubhouse, but a calmer, quieter way to spend a few hours....