I launch an 18 foot fiberglass Stratos, by myself - quite often. Here is my process.
I'm not the most nimble of people, and tend to run to the large size (no snickering Trep). I have a launch rope with a snap-hook on it. It's a 50 footer, large diameter. I hook it to the bow eye, and then walk over and tie it off to a cleat on the launch dock. If no dock available (not generally the case though), I will tie it off to a tree/rock.
I back it in slowly, until the boat just floats off. I pull up out of the water, stop, and then go get my rope from the cleat and pull the boat to the ramp - tie it off, then park the truck/trailer. I have an SUV and have on occasion climbed through, but prefer not to do that. Most ramps here, would require me to get my feet wet otherwise.
On putting it back on, I will drive up on the trailer, secure the bow line and winch, and either go in the water, or sometimes go back through the vehicle. Getting 'down' off the bow can be a lot simpler for me that climbing up.
Tex