I was driving home from the airport on Tuesday just before the snow storm hit and decided to check out the USDAA Nationals site since it was right on my way home. I have a photo album set up here on my Facebook account so I won't re-post all the photos here. The album is public so you shouldn't have to join Facebook or be my friend to see it. You can see an overhead site map here. USDAA is reserving fields 7-12 which are the middle set of fields south of the main stadium.
Looking west from the south-eastern edge of the fields. You can see the storm blowing in.
Looking north from the south edge of the fields
Looking southwest from the north end of the fancy turf fields.
Looking north from the fancy turf field shown above. There are restrooms in this building as well as a water spigot/hose/drinking fountain (but I wouldn't use it, see why below).
Bar adjacent to the main stadium. Looking north at main stadium (main stadium field is behind the building).
Overall the site is really nice. It was built 4 years ago for Denver's professional soccer team. There are lots of little parking lots surrounding the fields as well as bigger lots that are farther away. Not sure how USDAA will make use of those lots. Lots G and H were a fairly good hike from the site, probably not practical to crate in the car if you run multiple dogs. I didn't see RV hookups but I didn't drive into every single parking lot. The grass is beautiful-lush and green and there are 2 fields of fancy short turf that felt natural (Edited to add: According to the site's website these fields are artificial turf. The turf in the main stadium is grass though). All the footing looked really good in general though I didn't go out into the middle of the fields for a detailed look.
If you look on Mapquest you can see that the site is fairly isolated. The Rocky Mountain Arsenal 'Wildlife Refuge' is to the north and west and my advice to you is to stay the heck out of it. It was a chemical weapons plant and then a pesticide manufacturing plant in a previous life and was one of the largest, most contaminated Superfund sites in the country. Supposedly it was cleaned up but some years ago there was some controversy about that with toxic muck showing up in loose topsoil. Parts of the arsenal are open to visitors for hiking and Dick's Sporting Goods Park is constructed on land that was previously part of the Arsenal. Personally I won't go hiking on the arsenal land or drink any water on the site (there was also controversy about the toxic waste leaking into the groundwater). But I'm particular like that. I'm not trying to scare people and I am planning to go to Nationals but I do think it's important to be aware of these things.
Commerce City itself is largely industrial and economically depressed. I drove around the residential neighborhood to the northwest of the site and it's run down. There were some interesting characters wandering around. This doesn't bother me but I wouldn't send tourists there for a wander in their down time. There are some hotels/motels along Hwy. 2 between 64th and 72nd and unless you're a fan of dives I would avoid them. The Denver Renaissance Hotel is on Quebec just south of I-70 and it's a nice place that I believe allows dogs though I don't know their particular policies/fees. I've never been in the rooms but I've been there for my professional engineering group's meetings and it's very nice. There are some other hotels in that area too and I'd guess it's a 10-15 minute drive from the site. USDAA is reserving rooms but I have no idea where. I'm not familiar with anything else about the surrounding area. I didn't notice many restaurants when I was driving around but I didn't explore the entire area, just got a general idea.
One other thing to keep in mind when booking hotels is the oil refinery. It's at the Vasquez/Hwy 2 exit of Hwy. 270 which is also the exit for the site. The smell from that place is something special so I'd avoid any hotels downwind of that area.
Again I'm not trying to scare anybody or put them off of going to Nationals but these are things I'd want to know ahead of time so I could avoid them. Commerce City is very small, drive for 5-10 minutes and you're out of it. Downtown Denver is about 15-20 minutes away. Nice hiking areas in the foothills outside of Golden or Lakewood are 30-40 minutes away. Boulder is 40-45 minutes away, lots of nice off leash open space trails up here if you're done with your runs at 10 a.m. and looking for something to do.
If anybody local has more useful info. about the site or area please feel free to post to the comments. I'm not from around that area and I've shared all I know though if anything else occurs to me I'll leave it in the comments.