I find it hard to believe that an engine with 30k miles needs a bottom end rebuild. Is it using oil? My first suspicion would be that the valve stem seals need to be replaced. Used so little could dry out the valve stem seals faster. I don't see that keeping the engine from starting. I think you've got more than one problem. It's much more likely that the valve stem seals are fouling your plugs than the rings.
I'm with elau on going through the ignition components. If the plug wires are original, replace them. Also replace the plugs (copper, not platinum), rotor and distributor cap. Those are all common failure items and will run you a little over $200 for the parts. I replaced all of those on my M103 engine a couple of weeks ago. Very simple job. Randy Steele puts together a nice package that includes the suppressor cover and wire guides too. He's got one currently on auction
here. Rusty Cullens at
*************** will probably match his price.
The fuel filter is another maintenance item worth replacing, but I'd do the above stuff first to see if that fixes (or changes) the problem.