RE: DS3 Coax..

I not only agree with these guys but I can give you an example..

One upon a time in a job a long long time ago, I worked on a
data differential passing system based on Frequency Multiplexed
microwave signaling to send information up to 1000 feet.
We had a special interface on both ends, and a ground potential
leveling circuit. The coax was very similiar to what is used for
a DS3. In addition to the "data" coax we also ran a "grounding"
A number of times in the service of this equipment we had lightning
strikes, power surges, and grounding failures.
Everytime we had one of these events, there were major system failures.
Now this system was quite a bit more expensive than a DS3 mux, and
as I recall, none of our failures were under a solid 5 figure level.

We finally retired this old animal in 1993 after 21 years of faithful
headches. Thank you Uncle Sam..... That is a different story...
It was replaced with a fiber system and a backup high-freq RF system.

So with that thought of nostalga, I would defiantely go with a fiber link.
Even if you have to put a DS3 router on the COLO side of the park and run
Ethernet fiber across the parking lot.....

If you do this, it will be a much better idea. and much more expanable.
DS3 to a router- 100 Meg fiber...
This will even allow some monitoring for errors across the pipe...