If I were running a campaign that didnt allow for downtime, I'd allow instant creation of items via craft x & x feats via a craft points system.
As a DM, I like lots of downtime. There is no need for adventures to all follow on, run-on style. Who cares, honestly, what the non-crafters are doing? You dont even have to spend 5 minutes of *gameplay time* to say "Ok, you guys have a 6 month break. Jack makes 3 magical swords, a cloak, and 2 rings, Jim joins the thieves guild, and heads into the assassin PrC via getting to know the guildmaster, and everyone else does what they like." Then get back to adventuring. Or whatever.
I would be leery of the "Campaign plot hook railroad express" in any campaign with no downtime.
As a DM, I like lots of downtime. There is no need for adventures to all follow on, run-on style. Who cares, honestly, what the non-crafters are doing? You dont even have to spend 5 minutes of *gameplay time* to say "Ok, you guys have a 6 month break. Jack makes 3 magical swords, a cloak, and 2 rings, Jim joins the thieves guild, and heads into the assassin PrC via getting to know the guildmaster, and everyone else does what they like." Then get back to adventuring. Or whatever.
I would be leery of the "Campaign plot hook railroad express" in any campaign with no downtime.