As you leave the postal service make 2 rights and you will find yourself on a dirt road. At the end of it you will find a church and the achievement will pop.
For a Fast Achievement Guide check the link below:
Timestamps:
00:00 Intro + Day1
01:39 Day2 Intro
01:55 Day2: Higher Ground Achievement
02:22 Day2: Deliver Mail
04:39 Day3: Deliver Mail
05:24 Day3: Cat Lover Part 1 of 2
06:26 Day3: Deliver Mail
07:01 Day3: Workoholic Part 1 pf 4
07:19 Day4: Tower Watcher Achievement
07:57 Day4: Cat Lover Achievement
09:12 Day4: Movie Carrier Part 1 of 5
09:44 Day4: Deliver Mail
11:20 Day4: Movie Carrier Part 2 of 5
11:35 Day4: Workaholic Part2 of 4
11:46 Day5: Shutter Bug Part 1 of 3
12:19 Day5: Movie Carrier Part 3 of 5
12:51 Day5: Metal Detector Achievement
13:59 Day5: Deliver Mail
15:21 Day6: Shutter Bug Part 2 of 3
15:42 Day6: Movie Carrier Part 4 of 5
16:51 Day6: Deliver Mail
19:09 Day7: Workaholic Part 3 of 4
19:35 Day8: Interrogation
19:56 Day8: Shutter Bug Achievement
20:51 Day8: Movie Carrier Achievement
23:31 Day8: Deliver Mail
25:01 Day8: Free Spirit Part 1 of 5
25:46 Day9: Deliver Mail
29:03 Day9: workaholic Achievement
29:48 Day10: Deliver Mail
32:11 Day10: Free Spirit Part 2 of 5
32:25 Day11: Deliver Mail
33:54 Day11: Free Spirit Part 3 of 5
35:20 Day12: Deliver Mail
37:40 Day13: Deliver Mail
40:35 Day14 – Repeated 3 times
40:57 Day14: Free Spirit 4 of 5
41:10 Free Spirit Achievement (Ending 1)
42:31 Life in a Fast Lane Achievement (Ending 2)
43:29 Hometowner Achievement (Ending 3)