Tea, we discover our maintenance calories and exercise by trial and error. No calculator can tell you how many calories you can eat to maintain a weight loss or how much exercise is necessary. It's something that we all have to s-l-o-w-l-y discover for ourselves.
The maintainers in our Maintainers forum generally start off by adding in 100 or 200 calories a day until they hit their maintenance level. It's surprising how different that number is from one person to another! I'd say we have members successfully maintaining in probably a thousand calorie range. Unfortunately, there isn't any way of figuring out now what your maintenance calories will be when you reach goal.
I don't think that any of our maintainers have cut back on exercise. Everyone seems to exercise at the same levels and intensities that got them to goal. It seems to me that if you cut back on exercise, your calories needs would drop and you wouldn't be able to maintain on as many calories. Since most of us like to eat, we keep on exercising so we can eat more!
I realize that the numbers you posted are hypothetical, but the calories seem high to me and the exercise seems low. Did you know that the recommendation for maintenance exercise is 60 - 90 minutes a day? Dietary Guidelines for Americans
And you might be interested to know that in a survey of maintainers by the National Weight Control Registry, the average daily calories for maintenance were 1400, with an average of an hour of exercise. I wouldn't want you to be disappointed if you got to goal and couldn't maintain on 2000 calories with just a half hour of exercise.