You should seriously consider fibre optics. A 100FX link would do great, and you can get the transcievers for either end that turns it back into 100TX for use in any hub/switch. Using a makeshift combination of cheap cable and hubs doesn't sound like a very good idea. If it works at all, it would be plagued by collisions because of the latency introduced by the repeaters. No, you can't run over any type of cable without ruining it. If you want to cross a street, there are some decent short-range omni-directional wireless solutions available.
If the wire run is too long the signals will have attenuated too much and the equipment on the other side will see it as garbage. This will result in lots of re-sends, if it even works at all. You will also have a problem with interference from almost everything possible (RF, car/lawnmower ignitions, etc).
Seriously, look into fibre. The outdoor stuff may cost a bit, but it will be worth it in the end because you won't have the problems of a long run or multiple repeaters.