1. In med school I had to be out of town for 2wk-3mo at a time. I was always really nervous about being away from therapy but it wasn't as bad as I thought it would be. Phone calls once or twice a week with t and/or pdoc definitely helped keep me afloat.
For me, at least, I found that it was too difficult to do, like, Real Therapeutic Work over the phone. Not totally sure why--I just felt too bad afterward and it felt scary to feel that when I was physically so far away. Sometimes when I was only 1-2h away I'd drive back once a month or so to see one of the other of them in person, and that usually felt pretty good.
2. Usually I tried to schedule therapy calls/visits outside of work hours or at lunch. When I couldn't do that and had to miss work... it varied a lot, what I'd tell my supervisors. If they were jerks, I'd tell them something like, "I have a chronic health condition and I have to go to a doctor's appointment/keep in touch with my doctors." Which is true, if not the whole truth. If they seemed like they'd be sympathetic, I'd say, "hey, I've got a bad depression and I hafta get on the phone with my shrink for an hour or so." And really no one can say no to that unless they're a real jerk. (Granted, I work in the medical field... so at least theoretically, there are a few compassionate people who understand about mental illness. Maybe like 10%.)
Something that I think helped a lot was that I was always really careful to make sure all my work was done before I left, and that someone was covering my pager if I was on a phone call that couldn't be interrupted, etc... even if it meant getting in early or trading for an extra shift or whatever.
Now I'm in residency and have to work ~60h/wk (sometimes closer to 80-90) so it's pretty much impossible to schedule therapy outside of work hours. My residency director and chief residents know that I'm sick in this way... and it's in their best interest to keep me healthy (also they're good people) so they grease the wheels for me