Congratulations! It is "only an engine", after all.
Just to enlighten the rest of us, do you have any idea how many miles it took for your exhaust port to plug up so bad?
On your scored piston, if the rings are still a good fit in the grooves, the cylinder bore is still good and the piston not too loose, just ride it. From the performance you describe, it does not sound like you need a major top end rebuild.
Many 2 cycles have scored pistons from siezing up but all you need do is file off the high (shiny) spots and clear any burrs from the ring grooves. Use a file as abrasive paper leaves grains of abrasive embedded in the aluminum piston, doing bad things to the bore.
Don't get too many bugs in your teeth,