Hey Rachel,
Great customer management questions!
Customers are always first priority and in their eyes, they many not know you have other clients you're working on. Sure, they signed up with you immediately right after the first she's had a recent bad experience and your competitors aren't helping. The firs thing to do is to keep calm and be confident in your skills.
Here's the answer to your first question:
Your question actually is very valuable. What I've done in the past with customer objections and long winded answers where I find myself answering over and over again, is to:
1. Have Your Answer Prepared:
create a page or blog about it and add it to your "Customer Support" or "FAQ" or your "Why Work with Us" page. Tell your customers, "Thanks for your question and its a very common question customers have, whether they ask it out loud or not. Every niche is different and I undersatnd that the results you are looking for may not be exactly where they are today, but I can assure you my team are accomplished Search Engine Marketers.", then add that to the page.
2. Reinforce Your Answer with a Customer Review/Testimonial
Follow it up with a customer testimonial. Nothing builds confidence like a real review. Why do you think people make/made/lost money on Yelp ($YELP), Trip Advisor ($TRIP), etc. Google Business Reviews, Facebook Reviews, etc. Leverage your past and existing customers by always asking for a review even if they don't give you one until 2 years later like one of mine did. You really never know what you'll get and they're priceless.
3. Answering by Phone then Email Immediately After
Be prepared to answer the question and that your customer will forget everything you just said because it may sound like an excuse to them afterwards. Write an email that outlines exactly what you covered in your phone conversation and add links to the page I suggested to write up AND videos by Matt Cutts and reinforce in the email that these videos are from Head of Spam at Google (former or not). Matt has tons of videos about spam, naturally. I mean there's videos done by the Moz team, Rand specificially about spam and links vs quality content.
4. Reinfornce Your Answers AGAIN
Sometimes, I've had to tell a few of my customers/potential customers to, "Call any of my past customers; go to my website and look through my portfolio and call any of them"... depends how confident you are and hopefully none of your customers projects turned out badly. But if you can show your customers you have more confidence than your competitors whilst calming their minds and adressing their concerns you will be golden.
5. Show them Proof!
Nothing says, "I'm doing my job" like a nice chart. Google Analyitcs charts, whatever charts. An Excel spreadsheet with numbers and an embedded chart? why yes. Proof is in the pudding. Show them that the work you are doing is producing results and compare the metrics with your competitive research data, from the beginning to present. Show them numbers. Sometimes people aren't sold just by what you tell them. At the end of the day, they're just looking at numbers, so getting numbers from you is part of the status quo.
Here's the answer to your second question in four words:
Google Adwords Preview Tool
With that tool you can show your customers how they rank even when their in a different state. Make sure you tell them that Google's ranking system have changed over the years and local SEO is the reason. For example, It doesn't make sense to show results of a business that shares the same name but located in a different state B to someone searching from a state A. If its a very general keyword, let your customers know that Google is smart haha.
My final note is to just ask yourself, are you doing everything you can in your power/abilities to show them results they are expecting from you? If you are then great. You know what your capabilities are and what you can achieve especially if you've done this countless times before.
Don't forget to build great content for your business that reinforces all your customer questions especially if you know you're gonna get them over and over again. At the same time, you will have made great content for your site and Google will reward you for it too - BONUS!
I hope this helps you.