In-camera is indeed always 'best', but hey, DOF happens, so the oldtimers had a playbook of workarounds (and I just saw Jon's and Thomas' -- good ones.)
You might try the old Vaseline trick. Sandwich a piece of thin mylar, or similar, with the negative. Mylar on top/negative on bottom, with emulsion layer so that it will be facing the printing paper. Over a light table, or taped up on a bright window, smear a little Vaseline everywhere you don't want a crisp image. Back in the enlarger, expose as usual, with maybe a bit of supplementary burning.