Depends ...
Sometimes it's okay in mid-April, but other years it's still really muddy in May.
It depends on the speed of the spring thaw, how much rain we get, and whether or not they open the dam. The trails are mostly clay based, so the water can stay for a long time (and spring damage caused by bikes tends to last the whole season).
I was out there about 3 weeks ago, when it was still frozen, and it was great - very little mud. My guess would be that it is very muddy right now. If it stays cold, we might get a few frozen rides in until it goes above zero for good - then it'll be unrideable for a few weeks. Late April is usually a good bet.
If anyone gets out there in the next few weeks, please post a reply with the trail conditions.
And please .... don't ride Fanshawe if it's mud. We have to ride over the ruts and deal with the erosion for the rest of the season.