I'm a bit lucky in that my city is all gently sloped. My ride home from work is my reward (downhill). It took a bit to get used to it, but between the challenges in the gauntlet section, and some writing to shift my perspective to starting to get stoked about the rides. It became it's own reward. The writing really helped me.
You know how it's supposed to be impossible to stay mad while biting a pen (essentially faking a smile)? I find that writing and cheering can very quickly turn something you aren't stoked about to something you look forward to. At the end of your workout, grab a giant glass of ice water, plaster a smile on your face, and high five someone. Also, if you need additional support, join the strength and fitness challenge in my signature. I've been doing a few of the T25 workouts with my girlfriend after she gets home. I have a lot of options, and we just started those. They are good stuff. You know towards the end where the people start really sweating and kind of cheering? Join them!
Granted, to address the question of whether a semi active lifestyle is good enough, that depends on your diet and your genetics. For me, so long as I maintain a primal-esque diet (and go easy on the craft beers), I can stay relatively thin (~170lbs). However, even though I looked all right, I didn't have great endurance, strength, or tone. So I try to set specific goals that give me a reason to continue the strength training aspect. Stuff like doing a slackline, trying out for American Ninja Warrior, completing a tough mudder competition, doing a zombie 5K, and the like. So even though a completely non-active life would technically be okay for me, I had to set some goals that got me off my ass. YMMV.