When e-mailing a provider, what's a reasonable time frame to expect a response? If she doesn't get back with you in a few days, does that mean she's not interested? Is it better just to bite the bullet and give her a call? Obviously, I'm new at this...

The providers usually say what their response time will be. I would let that be the guide.

Keep in mind, providers have real lives too.  Depending on how far in advance you are trying to schedule, would depend on how long you give the lady to respond.  If I'm scheduling 3-4 weeks ahead, no big deal to giver her a week to respond.  If the date is for 3 days from now, I will have a plan B in place (not a date made-but I will give screening information so I can get an appointment fairly quickly).  It is wrong to make more than one date for a specific day/time and then cancel one of the two at the last minute.

Response time could be anything from a few minutes to a week or more.  If I've got your girl out traveling with me, she isn't close to her computer and I wouldn't suggest that she answer emails from guys when she is with me or even answer her cell phone at all for that matter.  Nothing bugs me more if a provider answers her cell phone when she is with me.  I wish they wouldn't even answer text messages when they are with me either.  I'm paying for their time to be with me, not text their friends or other possible clients.  You just need to have a backup plan in case you are in need a a provider on a rush basis because you haven't sufficently planned ahead.

I understand that some may think that we shouldn't deal with our phones at all when we are on the clock but we understand that if your wife/child/boss/employee calls YOU have to answer!

I don't answer my bat phone when I'm with a client but if I'm gone to Vegas for a few days (as I just was) I can't exactly explain to my family/friends that...I don't even know what, dropped off the planet?

In your business do you have an exact response time?  
Remember that this is our business & just because we accept a contract doesn't mean that we can ignore our other clients.

I try to answer emails daily & thankfully I've only travelled with gentlemen that understand that.
Hm, guess that kind of offended me, lol!