Having a vise makes life a lot easier. Not having one should not be crippling. I value my vises on my benches, but every year for 12 or 13 years I have done demos of hand tool woodworking at both the League of NH CRaftsman's 9 day Sunapee Craft Fair and at Wood Days at the Canterbury Shaker Village. At Canterbury only last year for the first time did I have a bench and a vise. Normally I was working on a 3/4" thick door placed on 2 sawhorses. I've made bowsaws, dovetailed boxes,and other things with just a few wooden C clamps to hold the work. I would advise drilling for round dogs. The holes can be used for holdfasts, a stop can be made by attaching a small thin square of wood to the top of a dowel sized to fit the holes, and you can of course use holdfasts in them. Creativity can't always trump the expenditure of money, but it can come pretty close to leveling things.
Dave Anderson
Chester, NH