Could not agree more on "too much stuff to haul around". Its a big reason why people free dive. Do much freedivng and you discover that the experience is different, much more focused on the "whole" experience, including the going up and down and what is going on inside you. Its just different.
The website :
www.deeperblue.com is the goto place for all things free diving. More info than anyone can absorb.
There are lots of free divers around, mostly younger and, around here, all pure spear fishermen. I like to shoot dinner, but would rather sightsee after that. Tiny is a freediver, good one too.
Average depth really depends on where I'm diving. I'm real comfortable, long dives and short recoveries, in 30 feet. Most of my spearfishing is 40 ft, don't like to spear with a sling(no line on the spear) in much over 50. Sightseeing can be down to 100, but dive time at depth gets pretty short. Sightseeing 70-80 ft is roughly normal in clear water.
Dive time: with a long recovery time and great conditions, average 1:50. That drops fast when you add current, waves, bad vis, etc.
Training: go diving with someone who knows how. Diving is the best training. Apnea walking and dry tables (look 'em up on DB) are good ways to introduce you to what its like to ignore the urge to breath. Long bottom times are primarily about getting comfortable and relaxing. There is lots of technique involved in the fine points and good gear helps, but you can get 7o percent of what is reasonably possible with relaxation and a cheap pair of long fins. Think 1 minute dives in 40 ft of water. If you decide you really like it and start doing it enough to acquire just a little bit of skill, take a course. Good ones are expensive, but best $ I ever spent.
Oh yeah, dive with a buddy. That gets very important to your life expectancy after you start getting good at this stuff.