Here's what I do when launching solo.
If there is a dock parallel to the ramp, I use the rope method. Leave about 12ft coiled up on deck, one end tied to the bow cleat, other has a carabiner which I clip into the stake pockets on my truck bed (I hook to the truck since it's further from the water), back down to the waters edge, take off straps, lift up motor, and put the plug in. Unhook winch and back in, once the stern is floating, stab the brakes, boat slips right off. Get out, grab the rope, tie off to the dock, and park the truck. If the dock is in the middle of two lanes, I prefer to put in on the upwind side, so the wind blows the boat against the dock.
If there is no dock, or it's not parallel with the ramp, I leave the winch hooked, no rope. Back in until the stern starts to float. Get out, climb into truck bed, unhook winch, climb over the deck, start up the boat and back it off the trailer, then beach or dock it.
Without a dock, I've found that the rope method doesn't work as well because the wind will push it off course quickly, and it's hard to jump in the boat or beach it without getting my feet wet. My trailer has side runners that hold the boat until I get it started and reversed off.
As with many tasks repetition is key to success. No two rigs load the same, and it takes time to figure out what works best.