Am really stuck on 4 - think I must have gone wrong somewhere - wonder if anyone can help me?!
21a City in Oman has obligation to welcome California [6]: -u---t
3d girl seen wandering around top of Bavarian isolated mountain [9]:
I-L-L-E-G
15d Happy to accept fashionable North America, for example [9]:
C-N-I-E-T [CONFIDENT would fit but I can't fathom out why!]
17d USA/Canadian border lake's tortuous trails - about 100 [2,5]: S- --A-R