Where to move 401(k) to start investing

[Bob Basting]

I've got a 401(k) with a previous employer that is not doing much in the market these days. I'm considering moving this into either a self-directed IRA (Checkbook) or a 401(a) under my own LLC. Any insight into either option? My understanding is that the IRA Checkbook option can be limiting in terms of whether I can work on the flip myself, not that I'm necessarily interested in doing so. What limitations have you run into with each option? Do all profit proceeds have to go directly back into the IRA or 401(a)? I'm looking for both retirement building and daily income supplement.