The mod containing compressed cobble is called “moreblocks”.
I have seen condensed cobble in two mods: one is called “condensed”, which may be server-specific (i.e., a mod made for the server on which I found it). The other was a modified version of the “moreblocks” mod (or possibly a fork).
As far as travelnets or travelling distances, there should be a way to travel back and forrth over distances, or else people will never venture far from their home territories. I know that one can set two homes plus spawn to TP to, but it’s not enough. My current home is several km from spawn, so i need a home point for that. I use my second home for exploring the world. (as of this writing, itis at approx -15,-15k). To do other things like mining, one needs more TP points. I currently have a cart track going down about 1km, and it takes several minutes to ride a cart there (or it seems to, anyway). If we had fall dampeners on the server, I could dig straight down and drop to the mine (I do this on another server and drop 1km/10sec if all mapblocks are loaded). There may be ores at great depth that will take ridiculously long to get to absent some form of fast travel. I think there is a mod out there somewhere that provides 5 or 8 waypoints that you can set, and then TP among them. That would be sufficient to me, but for people that want to have groups activities at a distance, they would want a method to transport their friends as well. My experience has been that servers without a fast or instantaneous method of long-distance transportation are less popular than those that have them.
(Sorry for spleling erorrs. The reply form is a tiny box in the lower left side of the screen, and therre is no cursor.)