I wouldn't really just make a bunch of backlinks to a redirected site. Not for the purpose that you seem to be going for anyway. You won't really receive any positive benefit just because of the domains age, and any negative effect from backlinking too fast will just have the same effect as if you had made it to the new site anyway. Since any positive effect from the backlinks might potentially be watered down and the negative effects are still possible it just isn't the best way to do it.
If you picked up an old domain and want to take advantage of any trust value based on it's age, then you should set up a page related to your keywords and then really do a massive backlinking campaign to the old domain. After you've built up as much value backlinking to the old domain and you're pretty sure it's stable, most of the backlinks have been found by the crawlers and the page isn't getting any penalty caused by the backlinking, then is when you'll want to set up the redirect. Doing it that way should get most of the value the old domain already had built up along with all the value you just built up passed on to the the new one after setting up the redirect.
A redirect doesn't work the same as a buffer site. If you're just going to immediately set up a redirect, then you might as well just backlink directly to the new site.
If what you're looking for is a buffer site then don't do the redirect at all. Just set up a link silo on the old domain, include backlinks from it to the new domain and then backlink the hell out of the old domain. Even in that case you'll be better off if you don't include the backlink to you're main site until you've already established a pattern of backlinking to the silo site first.
