The spiritual realm is handy for worldhopping, so it might work, but there are some problems. 1. Everywhere that there is land on Roshar, there is sea in Shadesmar. So you have to have a large amount of stormlight. 2. You have to be an Elsecaller or a Lightweaver. 3. You can enter from anywhere, but only exit from certain places. In general, traveling via Shadesmar is very hard.