Just remember that the iron on transfers don't wash out, so you will need to keep your stitching right on the line. You can easily trace a simple colouring book picture with your blue wash-out pen & stitch & then wash. Recently some of the patterns have you trace your lines with a very thin brown Pigma pen and then you stitch on that (it doesn't wash out though)
When I made the WinterWonderland quilt I used a red variegated Anchor thread.... I used a DMC tourqouise on another project.... Have to say it's alot of fun using all one colour, because you don't have to stop & start so often. I usually baste a layer of thin flannel or cotton to my base so if I need to carry the thread to another area, it doesn't show through.