I have that little project and it’s starting to come along. Unfortunately, the curve I used has bumps, so it doesn’t look smooth as it should.
Screenshot and Render:
Not sure on your question (I couldn’t find a way) but you may want to add an edge-split modifier to your curve. I set it to 45 degrees and liked the results better than a simple smooth on everything.
Gonna try that immediately after the endless render I inflicted on myself bumping up all soft ray shadows to get rid of the grainy AO… jeeez, gotta do some Octane tutorials A.S.A.P. and blend more, too long a break, I’m telling you.
Looking good! I don’t know of anyway to fill in the front other than position another mesh infront of it as you suggested. Or, convert the main curve to a mesh, add in your mesh for the front and join the 2 mesh objects into one. If you get it positioned almost perfectly, you can then select the front edge loop of the converted mesh, and the outside edges of the front mesh and ‘remove doubles’ playing with the limit until they are welded together, but that can get messy.