Hi and welcome!
I moved here from Enfield 14 years ago. It has a more villagey feel about it than Enfield and is more leafy and green, close to countryside and better connected for me when going to work by train or car. The train is also quicker from here into London but a peak travelcard is £17 with an annual all zones travelcard at £2660.
I don't know about the downhill thing, I think local shops all over are closing because of the penetration of supermarkets. I try and use the local shops ahead of the supermarkets, the butchers (and the veg stall outside) and the smaller shops, newsagents, pubs and restaurants.
You're right it is difficult to get an idea what a particular street is like but usually you're confined by budget anyhow. You can get a handle on crime rates and stuff from
http://www.upmystreet.com. I would visit at different times of the day and week. That nice looking green in the middle of all those houses looks great until you find the kids are kicking balls all over and screaming top of their voice every afternoon and weekend!
There are a couple of footpaths that leave the station, one going up towards the Cranborne Road which is about 10 mins walk and another up towards Strafford Gate.
I like it here, no plans to move unless work relocates me!