48 hours in Belgium. Brugges doable from BRU and back?

Checking the website of NMBS/SNCB (the Belgian national railways) you have early enough connections from Brugge to Brussels airport Zaventem, either direct of with a change at Brussel Zuid/Bruxelles Midi. Consideration is that any disruption on the line will cause you to miss your flight, and can show too late to make another arrangement. Staying in Brussels itself would be the safer option. There are very frequent connections from Brussels to Brugge, taking around 1 hr. Alternative is to have a taxi or shuttle service from Brugge, which could be expensive.

Ghent might be a good choice as well. There are direct trains to the airport at a minute or two past the hour that take just under an hour. so the 6:00 am will get there by 7:00, and the 7:00 am will get you there by 8:00, about as close as you would want to cut it. These same trains leave from Bruges 30 minutes earlier.
There are also a host of trains at other times requiring you to change trains at Brussels Midi.

That works the other way as well, direct trains from the airport to Ghent and Bruges, If you stay in Ghent, it is just 30 minutes to Bruges to visit there.

You are only there 48 hours.Stay in Brussels off the Grand Place Monday and Tuesday nights.
I stayed here http://www.ibis.com/en/hotel-1046-ibis-brussels-off-grand-place/index.shtml

Daytrip all day to Brugges on Tuesday so you lower the risk of missing your flight

I concur with your daughter, but also your concerns about getting to the airport. We're headed that way in the near future and upon arrival at Brussels airport, we're going directly to the train station and catching the train to Bruges. They run every 15 (or so) minutes and a direct train leaves on the hour (pretty close to on the hour), every hour. At the end of our trip we'll be in Antwerp and had the same concern as you; making a flight in the event of a train strike, weather, etc. So we're spending the last night of the trip in Brussels near the Grand Platz since it's closer to the airport, and there are multiple ways to get to the airport (train, bus, taxi,). As for Brussels itself, I've been there on multiple occasions and other than the main square, I don't feel it has much to offer, especially since I'm not a museum person. If you do go to Bruges, you'll probably need to walk around town until you can check into your hotel room. If you're one of those people who cannot force themselves to stay awake to adjust to the new time zone, then you'd probably be better off staying in Brussels. Because your time in Bruge would be limited, you don't want to spend it sleeping.

Thank you for your helpful suggestions & comments!

We decided to be safe and stay in Brussel city center, close to a train station near the Grand. We'll day trip Tuesday to Brugges!

On our return, we'll check out Ghent!