I used to have huge problems too. DD#1 is now great and when she's tired she'll just go into her room at Mum's and bash on the side of her cot until I put her to bed. DD#2 is still a problem but slowly getting better.

What I've done with both of my girls is mostly what you have described - go to a quiet room away from stimulation. I've firstly let them play in that room for a while - its quieter play without lots of people around though so they wind down a bit. Then I'll give a feed and hold her on me so she will gradually doze off.

TBH though, most of the time I just accept that they are just going to get a bit cranky and overtired from missing a sleep. Things got a lot easier with DD#1 when she started crawling and then walking - so much more physical activity really tired her out so she was much easier to get to sleep wherever we were.

Hang in there - and try to ignore the comments of ILs. Mine don't understand the parenting choices made by DH and I either and I'm constantly told I'm doing something wrong - mostly that I'm overprotective and that I'm spoiling my girls by cuddling them too much. You know your daughter so when you think she's tired, stick to your guns.