The 100 foot range of the "basic" familiar has been mentioned a fair bit, but I'm not sure it's as limiting as some people say.
Supposed it's daytime, and you have a hawk familiar (or another good flier with good eyesight). You send it up with instructions. "Go fly over that valley, look around, tell me what you see". It flies off, you very quickly lose telepathic contact... but it comes back and you get a report.
It won't have the same level of initiative a smarter familiar (or another PC...) will have, but you will still gain valuable information.