I'm a lecturer, 0.8FTE. But not in your area.
Teaching could eat up a lot of time, esp feedback and prep. But if you enjoy it, you should find it rewarding (most of the time). Even if you enjoy it, you may need to be ruthless about how much of your time you allow it to take up. Otherwise you could burn out, as teachers in schools can do.
Admin is not mentioned in this description, but will eat into your time. Committees, doing your bit for the department, pointless meetings, etc. This drives most people round the bend a bit. One tip is to volunteer to do anything you might remotely enjoy and then do it well, and be hard nosed about saying no to everything else.
Research - can be fun and the reason you want to keep in academia, can be pressurised - to get publications of a certain standard, or to get funding. Your dept should help you to get started but may not, frankly!
It is likely you'll feel you need to do more than 0.5fte, but there are ways and means of being ruthless about it.
One advantage of academia is USUALLY you have quite a lot of flexibility on where you work (and when) (but this can depend on institution and dept) and the year will have a rhythm to it depending on how your students are taught - I for example can work at home a lot in July, Aug, Sept, which is great. On the other hand, there are times of the year when I'm really under pressure, and those are of course the times when my dd gets chicken pox/flu/viruses...
I'd try and talk to people in the same field as you in other universities - e.g. not the one you are applying to, as they may well know the gossip about the dept you are looking at. Your department and your institution heavily affect how you feel about your job - they could make it a joy or a terrible experience. There truly are sick and depressive depts out there!
Hope this helps a bit...