"Getting to them is, however, quite another kettle of fish"
Actually, getting to them will probably be the lesser of your worries unless you just want to commit suicide expensively. Ecosystems are complicated, and finding a niche is hard even on Earth where all life has fundamentally co-evolved. Hard in the sense that there are masses of failures, both at the species and the individual level. This will be all the more the case for an entirely alien species (us) on a distant planet with its own evolutionary history.
Even if the lovely fantasy of a perfect human-supporting habitat devoid of competitors were to be found, staying a live long enough to take advantage of it would be a serious challenge as adaptation takes generations to accomplish. Either way, we should expect more than half of the human settlers to die before they reproduce - probably vastly more than half, so we'd have to send huge populations of settlers with a known high probability of snuffing it as part of the deal.
Only on Star Trek are small human communities able to settle stably on alien planets, and that's just because the writers ignore the science.