Where is the best place to live around FT Lewis (looking for a two-bedroom, two-bath house in a very nice area)?

Steilacoom. I had a 2 bedroom apartment for 900 a month.

Definitely check out DuPont, WA

Spanaway is nice, but more towards the 224th side, stay away from the 179th side. Then you take that back Roy gate, avoid traffic and quick 18mile commute. You also get a much bigger yard in that area.

Cost of living in Washington is a little higher than other places that I've been. If you want more out in the country but still kind of close to base, you've got Roy, Yelm, and McKenna are all out East gate which can help you avoid I-5 traffic. If you want to stay more in the cities/suburbs and contend with the hell of Washington drivers and the congested rush hour on I-5, there's Lakewood (careful about some places in Lakewood. Pierce County is the birthplace of the hit show that we've all come to know and love, COPS), Spanaway, South Hill, Puyallup, Dupont, South Tacoma, Steilacoom, take your pick. There are a LOT of options, all with their own pros and cons.

I see you are saying you want a lot to do. Anyplace from Federal Way to Yelm is going to be similar depending on what you want to do. Hiking? Camping? Fishing? Shooting? 4 wheeling? Each area has advantages and disadvantages.
Clubbing? Probably will make the 45 minute drive to Seattle anyway, or the less upscale ones in Tacoma.
What exactly are you wanting to do?

Dupont ,Washington....nice area and close to post

Steullacom, Dupont, and Lacey are good areas.

Dupont, Lacey are nice areas.

Pulallup, Olympia, Gig Harbor

Lacey. Better area to live in after hours and the commute is fine. Stay away from Tacoma, graham or Spanaway.