Well, I've only been running since November (been cycling mainly for the last 20 odd years), but a few injuries (ankle, mainly) have scuppered things a bit, although it seems I am over these now **touches wood**.
Most of my runs have been betweel 7 and 10km, with a few over 10km and one snowy 17km run.
All of my running, well as much as I can, has been off road, so I don't think the terrain will be an issue, and I won't be doing it in fancy dress
unless you count Skins tights, Gore shorts and a Craft top 