Redhill is quite a large area and gives you a choice of several areas of the twin, each with its own station, character and price tag to choose from.
The centre has some older houses plus modern flats and some rather grotty small estates. It has great access to the town facilities and station giving you half hour journeys into Vicoria or London Bridge (or bit longer to Blackfriars) if you get the fast trains. Some of the catchment schools in the centre are the less desirable ones. There is a large attractive park in the centre with nice play areas and cafes. The leisure centre isn't far from the centre.
Earlswood is part of Redhill, about 3/4 mile south and has more green spaces and mostly older houses in a range of sizes. It has its own station which is one stop from Redhill and lots of people who live there use a mix of Earlswood and Redhill stations, as Redhill is also within walking distance. Earlswood trains take about 40-45 mins as are the slower trains. It has a highly regarded primary school and for secondary children go to either Warwick or Reigste School (depending on where they live in Earlswood - Reigste School more sought after)
St John's is very near Earlswood but other side of main road and more villagey with a range of old houses and newer stuff and lots of green space. It doesn't have its own station but people use Earlswood or Redhill and it has a very sought after primary school St John's and the kids tend to go onto Reigate School which is about 1.5-2 miles away.
Meadvale is officially Redhill but equi-distant to Reigate. No station and a bit far to walk to Redhill or Reigate or Earlswood station probably. Children go to schools in Reigate and Redhill from there, depending on where they live.
Merstham is just north of Redhill. It has an area of Victorian housing plus a large estate of council/ex council houses and quite a few new houses being built. It has its own station which also has the slower trains running with the journey about 35-40 mins. It has 2 primaries which are pretty well regarded - one is on the estate and the other in the older part, plus a new primary and secondary on the edge of
Mertham.
Redgate isn't an official area, but named by estate agents. It's the area of Victorian housing on the border of Redhill and Reigate and is probably the most expensive bit of Redhill. It has green areas around it and is a good location for walking to Redhill station plus can be walkable to Reigate too. Children mostly go to the Redhill primaries and it probably isn't in the catchment for the popular ones like Earlswood and St Johns and can be borderline for Reigate School too - lots of children seem to go to private schools.
The most sought after Secondary is probably St Bedes in north Redhill - a cross denominational Church School with quotas for C of E, Catholic and FreeChurch - but very few places for those without a 3 year Church attendance record. Children go there from a wide geographical radius, with most being Redhill/Reigate and the villages nearby.
People commute from Redhill station from all of the above areas. parking at the station is under massive pressure and isn't easy so lots of people cycle or get dropped off. People also use Earlswood and Merstham stations which are also pressured for parking or some drive further in for cheaper fares.
Property in Redhill ranges in style and price. 3 bed houses can be got for well under £400k, especially as you go further south beyond the hospital. Larger 3-4 beds can also cost well over £750k in the more popular areas.