Greater Beijing area
 

Is there a nice landscape around greater Beijing area (2-3h travel time one way) for walking (ideally +temple)? There may still be smog - at least the landscape/nature should be nice,

Yes there is. My suggestions would be as follows, in order of recommendation (will let you do the googling research):
1) Badachu
2) Xiangshan (Fragrant Hills)
3) Tanzhe Si and Jietai Si
4) Hongluo Si

All of these are less than 1 to 1.5 hours from the central city each way, but I'd allot a good half-day+ for each excursion.

Great. Thanks.