If your league has been around for a while with roughly the same guys, I'd look at past drafts to get a sense of how many of each position tends to get drafted in each round.
So if you have, say, the sixth pick this year, you can determine how many players at each position are taken on average before each of your picks rolls around. So maybe at 1.06 you're looking, on average, at RB4, WR2, or any QB or TE. Maybe by 2.07, you're looking at RB8/9, WR 3/4, QB2, or any TE. And so on.
Grab the ADP information from any site (I use My Fantasy League, since that's the site we use for our league), and, for your 2.07 pick, cross of RB1-7, WR1-2, and QB1. Whoever's next on the ADP at each position is who's likely to be available.
Doing a mock draft for your league doesn't tell you that much, because you really don't care what player each individual owner is picking. You just care about what players are going to be available to you in each round. And this method is more effective: since you've factored in your own league's past drafts, your pseudo mock draft is going to account for the idiosyncrasies of the owners whom you'll actually be drafting with.
The online mock drafts have never been very helpful to me because the way they go does not reflect how my league's drafts tend to go. Our league tends to be less RB-crazy than the average league. More WRs and QBs (and even TEs) go early. My method better reflects that.
Hope this made some sense.