Hi all. 
I've been meditating since 2018. I have no formal lineage practice. I was introduced to meditation through Shinzen Young's Unified Mindfulness System and have made decent progress utilizing it to work on the untangling the sensory overload of trauma stuff.

But in the last year or so I've been experiencing a lot of champagne bubble type sensations, undulations, vibratory stuff- even not feeling parts of myself...and Other weird things happening to my body. 

i have a aphantasia so I don't see anything in my visual images space but lately every now and then some thing appears that I've never seen before.

I've been told that I might be tracking on the first Jhana with vibrational sensations, and I would like more guidance in long-term practice with the jhanas  and moving towards stream entry.

 I just listened to a Guru Viking interview with Leigh B and he spoke of his experience and seemed that long-term meditation retreats is where he got a lot of forward movement in his practice.
How do people go away for a year?
Where do they go?
How does this get set up?
Are there places like this in the United States or do I have to go to Asia to do this?

If I do something like this, what are things that I should consider?

I would love to know more about the practice of long-term practice in a retreat setting. I don't necessarily want to become a monastic but I'd love to hear how others do this and work towards making this happen

​​​​​​​thanks for any comments 

Do you want to do a long term retreat or do you just want to make progress?

Many of us here make good progress in daily life with just 30-45mins or 1-2 hours a day. 

Longer retreats can be useful at certain points along the way for sure and if that's really what you're after someone else should get back to you on that. 

In terms of the practice you're doing. How familiar are you with Mastering the core teachings of the Buddha? A lot of great info is in there about weird stages and experiences along the way. 

​​​​​​​Mctb.org, it's free online. 

How familiar are you with Vipassana fundamentals? Three characteristics, six sense doors? Or perhaps something like Mahasi style noting? 

For myself, if I feel I've plateaud or have stopped making progress I usually dial in the change on a practice level. 

If practice isn't generating the right insights then there's no guarantee that sitting for longer is going to help. 

If you want Stream Entry then you need a practice that's going to bring you insight. 

Concentration alone for many is not sufficient to cultivate insight. Just FYI. 

P.S. Tranquil Wisdom Insight Meditation is a very good approach that combines jhana, metta and insight in a way that really works for a lot of people. I and some others here can attest to this. 

Path to Nibbana by David C Johnson would be a good place to start. Though I wouldn't take their more religious beliefs too seriously. Except, if you're into that, then go for it. 

Long retreats usually (or at least often) require shorter retreats as prerequisites. For example, to be accepted for a 1-month retreat, they often ask that you have already done a one-week retreat. That makes sense to me because it would be easy to imagine people starting longer retreats only to find that it is not for them. So the first step in going on long retreats is finding shorter retreats and the communities that host shorter retreats.

By the way, I gained access to the jhanas on a non-residential weekend retreat and have been practicing them daily for years since then, so it is not always the case that you need long retreats to start or continue practicing the jhanas. I also don't think it would be all that difficult to learn the jhanas without a retreat at all, if you are included that way and are able to put in the time. 

There are lots of places to do retreats in the US. The problem is not finding retreat centers, but finding one that suits you and your practice, and before you can do that, you would need to have a good sense of what your practice is. Think of it like going to college. You would need to pick a major and you would have to do some research into what different fields of study involve. By the point at which you know that you want to practice in the Thai Forest tradition, or the Plum Village tradition, or the Burmese POI tradition, etc., you will have an understanding of the retreat landscape. 

If you describe your practice here (do you sit every day, how long have you been practicing? etc.), and mention the books and teachers you found important (you mentioned Shinzen already, and he's great, anyone else?) people might be able to point you to sanghas and teachers and retreat centers and books and so on. You might even consider posting a meditation log here.