My question is, if I pre order this game, will I be able to download the beta1 on another PC with High Speed, and then bring it home and install it on my PC?
With most products downloaded via Stardock Central, you can archive them, burn them, install them on an offline machine, then make a trip to the net machine and back to activate. I can't say for certain if that will be the exact case with sins, but it's a good probability. Note you do need to be able to install SDC on the net connected machine in order to do this.