The space elevator on Mars is attacked in Green Mars, IIRC. The series is awesome hard SF. Although KSR's prose can be a little dry at times, it's chock full of goodies. In terms of the process of colonization of the solar system, I would heartily recommend this series to the OP, as he makes a very plausible case.
Deciding on the order in which gravitics, fusion power and FTL travel become available (and how long between each milestone) leads to some interesting possibilities:
1) Fusion -> Gravitics/FTL is the standard, Traveller-esque model.
2) Fusion -> FTL -> Gravitics is the Foundation series order by Asimov. Gravitics come late, millennia after hyperspace is discovered. Also the case in Babylon 5, where you see ships with spin habitats and hyperdrives, and Traveller 2300AD, where gravitics are absent.
3) Gravitics -> Fusion -> FTL might be interesting, I guess the implicit assumption would be manipulation of gravity makes fusion economically feasible.
4) FTL -> Fusion/Gravitics. For some reason, I like the idea of fission-powered hyperdrives.
To garrowolf - I've found your inquiries interesting because they touch on many ideas I've been using in a 31st-century Traveller campaign.