May be it will hard to find it. But there is one more good way. Usually after an ICO is success the its bounty campaign participants will dump the coin, honestly it is not so good decision because even the development is in very early phase. Then you can buy it after they dump, you even can buy at lower price, this is an advantage for you. Then you only need to wait the developer do things in their roadmap and wait the price of their coin rise.
This really seems more like the simplest way to me than having to go through all the stress of finding someone outside your zone who you can trust, but you also have to consider that must be someone who knows how to handle themselves in the crypto environment without having to mess everything up and then giving you stories on how they got hacked and lost everything.
Even if you have to teach them what to do, you should know it is hard to even do it in person, let alone over the phone. Your best bet is to wait for the token or coin to get listed on an exchange, it usually gets dumped a little bit, but may not be up to the ICO's price, and if you trust that holding the coin will benefit you in the long run, buy and hold at that point. That still makes you an early adopter anyway.