It's quite normal for there to be a regression at around day 5 with PUPD so that can make you feel like a big backwards step. But you need the routine times to be suitable too. It's hard to know what to suggest in terms of A time with not knowing what suits your LO but if you record your times you can post an EASY here for me to look at. You don't want those A times too short, if there is a lot of resistance to settling that could be the reason. Maybe take him out of the room and try again 15 min later.
The modified method sounds fine. LOs who are learning a skill such as standing can't help themselves, they just automatically do it, even in their sleep!
You're right to see the positive side of it!!!
My DS adjusted brilliantly, he's so happy!
I was pretty pleased with my organisation (bragging there), I put together a basket for him with his toiletries, PJs a few days clothes, and muslins (his lovey). He also had a back pack filled with books, word search, toy, snacks, water bottle etc.
The day of the move the removal firm didn't leave until about 11pm. My DS is usually in bed at 7pm or just after and lights out at 7.30pm every day. He doesn't like to go to bed late, he really likes his routine, dinner at a set time, TV time, shower, read in bed then his night time CD song with a cuddle. It's very predictable. Of course none of that happened. At about 9pm we brushed his teeth and changed him into PJs then I put a duvet on the living room sofa, handed him a muslin. We didn't have his CD player so I employed the sleep song which is a huge sleep cue for him. It's been a long time since I had to sing it though. I sang it hundreds of times, at every sleep (5 naps per day and every NW) for about 2yrs before we switched to a CD - who knew I'd be using it when he was 7yo? The room was too bright, my MIL talked all the way through (open plan living area) with DP glaring at her to be quiet, the removal company were banging about with wardrobes... and DS listened to his song, smiled and said "I'm ready" and I walked away. he was asleep in seconds. By about midnight I had managed to make his bed up and I just went and woke him and told him he needed to walk up the stairs with me. He didn't even remember that the next day and was confused how he went to sleep on a sofa and woke in a bed.
Couple of days EW due to there only being one level of black out on his bedroom window. Once I got the second layer up he slept better in the morning (he's had 3 layers all his life now only 2).
I couldn't have asked for it to be any better than that. My DS has only ever slept at home and once only in a hotel so it's quite a big deal to sleep somewhere new.
Fingers crossed your move goes just as smoothly