US Immigration from Wales

So I filed in November last year and ETA for citizenship is Jan 2020. I've been unemployed and struggling a lot since I lost my job last year. I live in Seattle Washington and an incredible dream-job opportunity has come up in Vancouver BC.

I gather that I can't 'abandon my residence in the US' during the long wait time, but I asked a lawyer online about the prospect of commuting to Vancouver while still living in the US. He said that sounded like a great idea.

Is there anything else I'm missing? Anything that might come up in the interview about employment? would they object if I was commuting to Canada for about 6-8 months prior to the interview?

My ETA for the interview/case completion is Jan 2020. Now, I understand that this date could shift over time and it's not at all set in stone. It's been saying that for six months now though so it's fairly stable.

Question is, around when will I get my interview appointment letter? it's it pretty close to the estimated time? or a little in advance?