What do you all like to use in the way of attachment systems/heads to get from a skater dolly to your videocamera?

There are lots of options.

HiHat, tripod, home made post with a stud for the head or HiHat, or just a 3/8 bolt to the bottom of the liquid head.

The easiest is just your tripod. Most tripods like my Miller solo allows the legs to spread a lot so you can get very low, and of course you can just screw some empty catfood cans or whatever to your board to make more secure places for your feet.

I always add sandbags to the dolly to make it run smoother, and you can then also attach an elastic chord to the middle of the tripod for safety.

Just a few thoughts.