Nuclear power would be the easiest, and would certainly require the smallest change in infrastructure, but renewable sources are still tenable.
Power density is actually not as much of an issue as you think it might be, it just requires people to accept individual wind turbines and solar panels in addition to more centralised power generation, (for example, a hydroelectric dam if you live along the east coast).
I used to live near Albany in southern W.A., and the wind farm (which did not actually take up that much land) was enough to provide ~75% of the region's consumption. Supplementing this with private generation would be rather feasible.
Incidentally, geothermal isn't that limited in location;
Distinct from hydrothermal, HDR / EGS may be feasible anywhere in the world, depending on the economic limits of drill depth.
Tidal is far more limited, as it requires coastal regions with relatively high tidal flow, but even then it's still not that bad considering the vast majority of our population lives spitting distance from the coast.
Whatever the case though, the key to successfully utilising alternate energy is to make use of multiple sources concurrently, rather than relying on an single source.
Regarding nuclear, while yes, uranium reserves are ultimately limited, the rate of consumption of uranium is
far less than that of coal, especially if you make use of breeder reactors (which can also utilise the far more abundant element thorium).