Originally Posted by Jos Stratford
Yes, I did a summer trip, though same does apply in autumn (but accommodation becomes harder at reasonable cost). I took the train up and got local accommodation - as I remember, a bike was free and besides the best areas are all walkable from the centre (albeit at a degree of risk of Polar Bear - saw several while on foot, one stalking us as we retreated from a headland). Belugas were abundant and would swim underneath you at the main jetty. Rented a truck for one day to explore the very limited road network that radiates out a few kilometres from the town.
Rail track is generally in poor condition and the train groans a lot as it trundles at a very painfully slow pace across the many hundreds of kilometres of tundra. I believe it is currently not operating due to flood damage earlier this year., menaing air is the only means of access.
I did a similar trip to Jos last July, and the train had been out of action for a while due to flood damage, with no immediate prospect of repair. We flew in which was expensive so I'd say yes, you can do a DIY trip to Churchill, but it can't be done cheaply at the moment.