I'm trying to book a trip, BWI-BDL-DCA.

US has the most flights and options for the route. The US web site is charging about $240 for the trip.

I'd like to book on UA's web site, so the miles will automatically drop into my MP account (at least in theory. I flew to Montreal in May, booking on UA's web site, and flying AC Jazz. I'm still waiting to be credited the miles for that trip, even after sending a letter.)

Unfortunately, UA's web site is not listing the same flight options the US web site is. And UA is charging close to $500 for the trip.

Question: What's the best way to make the reservations for $240 and insure the miles flown on US will be credited to my MP account?

Thanks!

Max