Dave,
The magic trick to disassembling most, if not all, of the Ruger P series is pressing the ejector down and forward, locking it into position there. I made the mistake of forgetting to do this myself long ago when I first got this pistol, as do many new owners of these.
Unfortunately, such is not the case now. I've triple-checked everything I can think of, plus followed up on several suggestions of others, to no avail. I'll be calling Ruger tomorrow.
Although prices may vary by region, your P-94 should be worth $300 IMO. It has less use than mine, and twice the number of mags, so I think that balances out the new and aftermarket parts in mine. (Another dealer at the aforementioned show only offered $250, but they struck me as kinda sleazy. They were selling another Ruger P-series for around $350, and it was not nearly in the same condition as mine. I think they were trying to lowball me in order to make a quick $100.) Two reputable dealers I know, including the one who offered me $300, sell used guns, often on consignment, for 10% profit.