Virgin Atlantic can be a great option (transfer partner of nearly every major rewards program) and it's certainly possible to get from North America to LHR for under 100k round-trip in business class on either Virgin or Delta via Virgin, particularly if you are on a direct flight. That's a case of where it might make good sense to do a positioning flight to JFK or BOS beforehand, though, and you'll have to watch out for fees and taxes even on award fares that can become staggering to the UK (the UK charges higher fees the closer you get to the pointy end of the plane).
Delta also has frequent flash sales for Delta One to Europe under 100k, and I think Singapore still has a Houston-to-Manchester 5th Freedom route with a fixed award chart, which is likely a pretty luxurious way to get there. If the fees are staggering on award fares, it might be a better option to consider flying into CDG or AMS instead of the UK and catch either a short flight over to your destination in the UK (or just hop the train if London is your final destination).
Air France/KLM is also a transfer partner of essentially everyone, and it may be worth spinning the wheel to see what comes up there. You can get some great bargains in business class or some insanely pricey economy options (often on the same flight!), and other craziness like ORD-JFK costing more miles than the same ORD-JFK flight and onward to HKG. As odd as things can be there since they got rid of the award chart a few years back, it's still definitely worth looking.
The trick with Virgin Atlantic is that you need to find availablity on partner metal, preferably Delta. There are fuel surcharges, but also government taxes and fees. Just the UK taxes alone on a business class award can be about $300 more than economy!
Have fun in Salem. Just wave in a southwesternly direction on the other side of the tall buildings!