On the topic of Thaumcraft entry gating.. interesting timing, as this weekend I've been working on a bee-line progression to golems.
I had forgotten about the dragonstone requirement, and having to work up to that has effectively doubled my time to reach them. Before that lapse, I had my lapis crops planted by Minecraft day 24. (This includes a good 3 day delay while I dug around for lava!)
I didn't have diamonds, blaze, or gold in my original plan, and spent extra time getting those seeds and growing them. I'm currently on Minecraft day 38, waiting for blaze essence to grow so I can make sparks for terrasteel. In another 2 or 3 days I should be there and waiting for the Greatwood to grow, then finally getting the Thaumcraft research for the golems and harvest core. So, assuming I haven't missed anything major, I should have harvest automation before day 45. I think the biggest hold up now is actually getting the ember moss.. have gone through over a stack of mutandis at this point and still no sign. I wonder if there's a quest somewhere that will reward me some..
So, you can have golems within 15 hours of play, and I'm thinking that could be brought down to 12 hours with better planning. This seems pretty reasonable to me.
My Witchery and Botania areas are thrown together (I'm not a builder to begin with). All of my tier 1 seeds are 10/10/10 and most of my tier 2 seeds are close. In this world, I've ignored most of the storage quests, and all of Mariculture (minus the vat for getting to the Nether), Forestry, Tinker's Construct (I'm still using flint tools!), BC, and Railcraft. Interesting to note that progression down these tech lines is not needed at all for the magic side.