No, I usually work the whole thing through to pre-master stage in Mulch.
I usually start by building up a lot of looping elements - which is what I was doing with MIDI sequencer + sampler / synths. Sometimes this involves a clear A/B section - e.g. two basslines, sets of chords, etc. in which case I usually put each section in its own mixer so I can mute one or the other with a single click.
Before attempting to structure out a track I sometimes export loops I've made so I can basically work with my own riffs as if they're samples. Play them back at different octaves / half-speed / double-speed / etc. I'm quite into sequencing bits in reverse, exporting them and then reversing the loop.
Then I use a lot of automation to mute/unmute/fade/filter in/filter out elements. I'm paranoid about just having a bunch of loops coming in and out, though, so usually part of this automation will involve working with making variations as the track's structure comes together. I re-work bits, add variations / fills, throw in little one-off events. Lots of messing with little sample-and-hold VSTs, adding harmonies via granulators, shifting stuff to be in new phase relationships with the beat. Again, that requires more automation to drop things in and out or switch presets.
I don't have any kind of MIDI controller, so my approach to automation is largely programmed, although I do sometimes record parameter tweaking I do with the mouse.
I met Mulch's creator while living in Melbourne, Australia and he basically told me he thought I liked to do stuff the hard way.
Haha. he basically couldn't figure out why I'd ended up using his product for sorta trad beat-based stuff... Ah well.