In the interest of accuracy...
A malp cant hold a gate open for more than 38 min.
The only things that can do that are insanely large power sources, normally black holes, although the Asurans do have a means to do it.
Maybe have a button in the control room, and on the DHD to dial it, and then it shuts down after a minute, then you could have the DHD and control room button away from there gates, to promote more team work.
Also, the gate is one-way, and there has never been any hint of it being changed somehow. The only thing that's two way is sending energy signals through, as well as gravitational fields etc.
A ring transporter could probably go both ways, but would be a bitch to map.
Also, who says all has to be well at the SGC? you could have the aliens having already attacked, and the place in disarray.