The potentially frustrating aspect to this whole investigation is that much will probably not be known whilst it is ongoing. The Trump administration will almost certainly try to distract and distort during that time. If we have some long stretches without much or any news, Trump's team and surrogates may well try to declare that silence Mueller's team has found nothing of concern.
So the bottom line is: ignore the distracting noise out of the White House about this investigation.
In the meantime, Mueller may be the type who uses selective leaks to keep Trump-led distortion and dissembling from happening. Let's hope so. This investigation may be ongoing until late into the year and even well into 2018. Better to take its time than to rush.
Fortunately, to a certain degree, the whole scandal has significantly paralyzed and handcuffed Trump. It would be better if he had not become President, but given this is the hand we must now play, the more hampered he is, the better.