I carry the same small duffle bag in the TC that I did with a TT, FW, and just plain ole tent camping. Probably weighs 5 pounds. As the vehicles have become more complicated, the need for a lot of tools has dwindled. If you have the basics covered, you would be good.
Water hose breaking - 3 or 4 hose clamps. Let cool, wrap area with cloth or two layers of duct tape, tighten hose clamps, then leave the radiator cap lose so the system doesn't lose pressure.
Belt - with todays single belt system, just carry a spare belt and the tool necessary to change it - usually one wrench. Or better yet, change you belt out every 5 or 6 years and you don't need to carry a spare.
Electrical - wire cutters, stripper, and a few feet of #10 wire. Also volt meter to help track down the issue.
Basic - screw driver set, usually 2 or 3 of each.
Roadside service card - you don't necessarily have to get a tow to a dealership. They will tow you to your requested destination which could be an auto parts store where you can do the repair yourself.
If you want to carry a bit more, just grab a cheap 108 piece set in plastic case that will probably weigh under 10 pounds. However, I figure that if I need those type tools, I'm not going to have the part I need anyhow. When I get some place that does have the part, they will either have the tools I can borrow or there will be a place next door where I can buy them for $25.
At home I have the tools to tear a car down to every nut, bolt, and screw. But on the road are you really going to have the place to fix a major problem?