Do a test. Place some small trades on a stock from one of the non US markets (London for example). You don't need a market data subscription for this. Just give yourself trading rights for that market if you haven't them yet (use Account Management). Watch prices from an external source (e.g. Google).
Sell a one lot of a back-month straddle on a high dollar stock, provided you're not on the 90-day PDT suspension. The credit will keep you above $25k on cash-balance.