Hi Daniel,
I've read many fine reports from Panditarama Lumbini so it's been my primary focus.
OTOH, in Myanmar at Panditarama Forest Center in Hse Main Gon they conduct what's called a Special Sixty Day Retreat during December and January geared specifically towards foreign meditators.
One thought was perhaps going to Lumbini in Nepal for 4-8 weeks sometime in September – November, and then either staying on for some time longer, or heading to Myanmar for the Sixty Day Retreat in December/January, based of course on where my head was at after the Lumbini retreat.
MBMC isn’t easy to get solid reliable info on and from what I read online is unclear.
I've read Mahasi's books and other variations of noting and done it a little, but not full bore. A week ago I ran into Burmese Mahasi monk (and meditation teacher) on the street here in Brooklyn (orange robes) and had a good conversation with him. He resides at a temple 6 blocks from me that's part of the America Burma Buddhist Association (ABBA). He's been in the USA for about a decade. We talked about meditation and while I mentioned my interest in Mahasi, he said he'd done a 10-day U Ba Khin retreat and found it very beneficial, and thought the anapana (5 days*) was challenging and developed concentration. Although I think they are geared more towards the Burmese population in NYC, I'm considering meeting with the head monk and seeing if there's a way to get some Mahasi instruction there.
One tertiary interest is that I’m a climber and Nepal offers an opportunity to see the Himalayas, perhaps do some site seeing/trekking pre or post retreat.
*From my understanding U Ba Khin's 10-day course originally was structured with 5.5 days of anapana before teaching Vipassana/body scan. However, Burmese politics changed and foreigners were only able to get a one week visa, so the course was changed to a 7-day course, with the first half (3.5 days) devoted to anapana. Goenka's courses retain this 3.5 day anapana structure. The IMC course I took recently devotes 5.5 days solely to anapana.
Lumbini gets a lot of good press and reviews these days. Panditarama has a place associated with it that is a bit more suited for westerners and more designed for them: might look into that if you want to brave Myanmar.MBMC in Penang also takes Westerners: could check them out these days: teachers vary and how good their English is varies.Given a choice of all of those, I would think about Lumbini first.I would read Practical Insight Meditation a few times and practice the basic techniques in it to get them down pat.