There are some key things of note:
Rey's flashback vision has Yoda saying "Its energy surrounds us and binds us" (a memory of Luke's, and a line that Yoda says in Empire Strikes Back just before saying "luminous beings are we... not this crude matter"), and Obi-Wan saying, "Rey... these are your first steps" (the latter words of which extend beyond the duration of the vision, at least from the perspective of the viewer).
Unless we are to interpret this as:
(A) a memory of Obi-Wan's force ghost speaking to Rey at some previous time (like when she was a toddler taking her actual first steps),
then we must interpret it as:
(B) Obi-Wan's force ghost speaking to Rey in the moment.
Interpretation (B) would be consistent with the temporal flow of the vision, since:
The vision starts in the distant past with Yoda's quote from Ep.5 and the Cloud City hallway scene, and it ends in the future with a vision of Rey's fight vs. Kylo in the forest. At the start of the future vision is when Obi-Wan says, "Rey...". Therefore it seems consistent to think he is talking to her in the moment, because his words come at the junction of past and future.
If that's the case, and he is speaking to her in the now, that could very well mean that, perhaps throughout the film, Rey has guidance from the beyond, much like Luke Skywalker did from at the end of Ep. 4 when Ben consciously guided him to close his eyes and destroy the Death Star, and at the beginning of Ep. 5 when Ben appeared to him and told him to go to Dagobah.
Note the parallel:
When Kylo has Rey pinned against the edge of the chasm and he says, "You need a teacher, I can show you the ways of the Force," Rey is reminded of Maz's words, "Close your eyes. Feel it. The light. It's always been there. It will guide you." She closes her eyes, then proceeds to do the near-impossible.
This parallels Luke closing his eyes at the end of Ep. 4., then proceeding to drain the perfect shot.
So yeah, Rey has some guidance. Whether you want to believe the Force itself is guiding her, or that someone's ghost is guiding her through the Force, it is the same thing, because in order to have influence in the real world through the Force, one must become one with the Force. Therefore there is no distinction between Rey being guided by the Force itself, and Rey being guided by those who have become one with the Force. (The meaning of "one with" is specifically that the self and the Force become one thing.)
As Qui-Gon's ghost tells Yoda in Ep. 3:
Qui-Gon's voice: When I became one with the Force, I made a great discovery. With my training, you will be able to merge with the Force at will. Your physical self will fade away, but you will still retain your consciousness. You will become more powerful than any Sith.
Yoda: Eternal consciousness.
Qui-Gon's voice: The ability to defy oblivion can be achieved, but only for oneself. It was accomplished by a Shaman of the Whills. It is a state acquired through compassion, not greed.
Yoda: ... to become one with the Force, and influence still have... a power greater than all, it is.
Qui-Gon's voice: You will learn to let go of everything. No attachment, no thought of self. No physical self.
Later, Yoda tells Obi-Wan about this and offers to train him in it, and Obi-Wan acts surprised.
Obi-Wan: Qui-Gon? But, how could he accomplish this?
Yoda: The secret of the Ancient Order of the Whills, he studied. How to commune with him, I will teach you.
Obi-Wan: I will be able to talk with him?
Yoda: How to join the Force, he will train you. Your consciousness you will retain, when one with the Force. Even your physical self, perhaps.
Now we know that Luke never finished his training before Yoda became one with the Force, and therefore Luke would never have had the opportunity to learn the secret of the Ancient Order of the Whills. The fact that Luke missed this key training explains the following line from Ep. 7:
Han: The people who knew him the best think he went looking for the first Jedi temple.
This temple almost certainly the home of the Whills. We certainly see Luke feeling the requisite compassion:
(From Ep. 7 script): IT IS LUKE SKYWALKER. [...] He looks at Rey. A kindness in his eyes, but there's something tortured, too. He doesn't need to ask her who she is...
There is also the fact that Alan Dean Foster's novelization of The Force Awakens contains:
a passage from the Journal of Whills
It seems pretty obvious, then, that:
Luke went to the island to learn the secret Qui-Gon spoke of, and possibly, even more. Rey's dreams of the island, which we learn of when Kylo interrogates her, were likely planted in her mind by Luke (or Qui-Gon or Yoda or Obi-Wan) through the Force, using a technique similar to the one that Darth Sidious uses to plant dreams of Padme's death in Anakin's mind.
However I think that Kasdan and Abrams did not want to overstate the role of Rey's male Jedi influencers, since that would tend to weaken her own character. Ep. 7 is Rey's coming of age story, much like Ep. 4 was Luke's. But it was better for Rey's character that they chose to leave it up to viewer interpretation, and let viewers infer and establish for themselves that the Force itself guided Rey.
There is also the possible explanation that if Obi-Wan or someone else was influencing Rey through the Force, she would not be able to consciously recognize it anyway, since she had never met them. After all, no one ever sees a Force ghost of someone they they never met—Qui-Gon's ghost conspicuously does not appear at the end of Ep. 6 (except in this fanmade YouTube video—but even there he waits to appear until Luke's back is turned, heh). This inability to distinguish the Force voice/ghost of someone you've never met is consistent with the fact that the Force and the person are one, and it's also consistent with:l the fact that:
Yoda's and Obi-Wan's voices in Rey's vision are so quiet and subtley planted that most viewers did not consciously recognize them the first time around.
However the drawback of the writers' choice to make the Force's influence on Rey a subconscious one, is that it resulted in many viewers finding Rey's progression to be unrealistically fast. It led to questions like the op's above: how could Rey have done all these things without any kind of guidance or training?
It makes a lot more sense whn you realize that she (and also Fin, I would argue) had a whole team of dead (and one living) Jedi guiding them as best they could through the Force, kind of like guardian angels.