Help with Daily Calorie Allowance... BMR? TDEE?

LWlosingit

I just recently stopped using Weight Watchers Online and am trying to determine my calorie allowance for MFP. I've seen a million different ways of calculating and I know that ultimately I'll need to determine the number that works best for me through trial and error. Just looking for some advice on where to start.

I'm a 27 year old girl, 5'8". I work at a desk 4 days a week for 8 hours each day. I'm not consistently active, though I'd say I go for long walks (60-75 minutes, fast pace) 1-2 times a week. According to my HRM I burn about 500-700 calories from each walk. I'd like to increase my activity level.

My TDEE for sedentary is 2219, 3x week light exercise is 2543
My BMR is 1711

Where would you start for calories/day if it were you? Should I calculate based on a sedentary lifestyle and then eat back the calories I burn through exercise?

Any help is appreciated!