Cross training - a good idea?

There's been a lot going on lately as evidenced by the past few posts. Reflecting a little more on my reaction to down time, I realized today that I deal with the anxiety of idle time that leads to an over active mind by being active. It helps to channel some of the idle energy into something productive while the rest is used to assemble my thoughts in a constructive way. To that end, I decided to go for a run today. Attempting some cross training 5 days before the first mountain bike race of the season is probably not the wisest of moves but I never claimed to always follow logic... I spent 50 minutes running the trails at Green Lakes and felt fairly well, even good at points. By the end, I was hobbling a bit as my knees were screaming at me to stop but I chugged my way up hills and loped my way down them without pausing for a breather. Even passed a mountain biker who was struggling through a particularly root-filled section of trail. 

I am not sure how far I ran but in 50 minutes, I estimate it was about 5-6 miles. Not bad for the first run of the season. We'll see in a few days if this was such a good idea.