I will be picking someone up at Swampy and then going to Don Muang to fly out but could have anywhere from 4 to 5 hours gap

If there are delays then no worries, hang out in Don Muang but if I get there early I don't want to hang around but also don't want to go all the way into BKK.

Are there any nearby Malls to Don Muang or districts that I can get to easily to grab some street food or a beer even rather than stick around the airport?

FYI, the Henry J Beans at the Amari Don Muang Hotel opens at 1700 hrs, just across the highway via skybridge. Good hangout spot.

Mac

I find Henry J Beans over-priced.

As street food was mentioned there are several place over the airbridge and opposite the Amari. More near the station.

Much better than that is the Bridge which is actually on the Amari airbridge just before the escalators to the hotel reception. The lunchtime buffet benefits from Amari quality but does not suffer from Amari pricing. i think the buffet is 140 Baht.

I avoid buffets like the plague but this one I would actually use and recommend.

you could head to FUTURE PARK RANGSIT. a few kilometers away, but easy to get to by both Taxi or public Buses (9 Baht for a non-AC Bus).

I find Henry J Beans over-priced.

As street food was mentioned there are several place over the airbridge and opposite the Amari. More near the station.

Much better than that is the Bridge which is actually on the Amari airbridge just before the escalators to the hotel reception. The lunchtime buffet benefits from Amari quality but does not suffer from Amari pricing. i think the buffet is 140 Baht.

I avoid buffets like the plague but this one I would actually use and recommend.

that buffet is operated by AMARI themselves ?

FYI, the Henry J Beans at the Amari Don Muang Hotel opens at 1700 hrs, just across the highway via skybridge. Good hangout spot.

Mac

Cheers, but this will be 10am-ish to about 1pm-ish

you could head to FUTURE PARK RANGSIT. a few kilometers away, but easy to get to by both Taxi or public Buses (9 Baht for a non-AC Bus).

I did remember you can get a bus to Chatuchak, I think there's a Mall around there?

Is going to Future Park bus from outside the airport or do I need to make my way down to the road or something? Good call, will investigate this

From DMK, to head to Future Park you walk across the footbridge for the Amari Hotel and take the Railway Station exit to street level. Easy to hail a taxi from the roadside.

Near Chatuchak is Central Plaza Ladprao, about a kilometre DMK side of Morchit BTS.

On the way to Future Park is Zeer Rangsit if you are interested in IT (plenty of eating options also). Get out at BigC/Bobae Tower opposite the Asia Airport Hotel and walk across. Future Park or Zeer are the closer options.

Much appreciated

Close to Central Lad Phrao and thus close to the express way to Don Muang a newly opened place called The Fat Cow... Opens at 11 am... until 11pm, I belief. Good beer selection and pub food as burgers, wings and Caesar salad and the likes...

On corner of soi 15... my condo around the corner.. makes me happy to have a place like this close by!

+1 to Zeer Rangsit even if IT/smartphones etc. isn't really your thing.

Lots of places to eat/drink, cheap clothing and all kind of gadgets for sale on the basement floor.

Thai-style market in front and around the building with a lot of street food stalls.

Small single-floor shopping mall in the building just next to the main building (on your right when facing the main building, entrance is right where the green W logo for Watsons is on the picture above), has lot of clothing, bags etc. of all prices including good quality local brands (e.g. "No Problem" shirts). A lot of choice in a small area, really.

Much closer to DMK than Future Park too.

I could spend a full day there without getting bored, but admittedly I'm an IT geek

Get to the other side of the road and on a bus #59 or #29. Get off at the shopping mall called Future Park Rangsit. There is a Sizzler on the Ground Floor (called 1st floor AFAIK) on one side of the building. And a cinema. Besides a Swensen's ice cream parlorand more eateries than I can name, including a Thai buffet (in the basement). MK Restaurants are there, too.

Catch the bus back outside Major Cineplex.#29 or#59 again, but there are also vansleaving from the parking lot of FPR.

There's food and beer available in the airport and no worries about getting back in time for your flight.