There is also no other way out of the energy bottleneck.
That said, there needs to be more than one approach, like the Manhattan Project. I think a kinetic containment is much simpler and more likely to produce >1.0. (Like a giant internal combustion fusion engine since fusion is scalable as large or small as you want.)
Thorium looks good.
There are several. IMO, the most likely to be successful is the "Bussard polywell" approach. A real nice "twist". It uses magnetic confinement to contain a cloud of electrons (due to low mass of electrons, they are FAR easier to magnetically contain) to create one electrode of an electrostatic confinement system (cf "Farnsworth Fusor"). Funded by the Navy and in "second round" (scaleup) of funding.
See "Talk-Polywell" for a forum that addresses this (and some other smaller efforts (Focus Fusion, and ever Rossi's LENR)).
“There is also no other way out of the energy bottleneck.”
To echo agere_contra, yes there is: thorium. Here is an excellent article on the subject (which also debunks some other alledged solutions to the energy bottleneck): http://market-ticker.org/akcs-www?post=183373
FYI, thorium is not a permanent solution - according to the above article, thorium from coal (and the liquified coal that we can use for our vehicles) will “only” last for about 200 years...more than enough time to develop fusion and some better battery technology to store all of that energy.