Dont go into using sketchup, its really hard to export. You need to buy Sketchup, which is about, 400 dollars if I remember correctly...?
Try using Milkshape, I use that. Its really simple, it can export directly to .dts(the format that blockland uses), and it can also do all the advanced stuff. Get the trial, see what you think.
EDIT: I made this yesterday, it took about an hour.