Hi Leanne,
My situation is/was very similar to yours so I will share my experience. I am a Canadian who was living in the U.S. for over 15 years. My husband of almost 14 years is a U.S. citizen. We started to consider the possibility of moving to Canada last year and at the time I had U.S. PR status. We decided it was best for me to pursue U.S. citizenship before leaving the U.S. because I had been eligible for it for several years but just never got around to getting it/didn't want to spend the money on it. I know that the U.S. really frowns on people with U.S. PR status leaving the U.S. and if you are gone for more than 2 years, you risk losing it and having to re-apply and I have heard of them denying people applying for the second time. A friend of mine from the U.K. is going through this process right now as she is trying to move back to the U.S. Being married to a U.S. citizen and having U.S. citizen children, you just never know when you may want/need to move back to the States and you are not guaranteed to get your green card back just because you are married to an American.
So if you are eligible for U.S. citizenship now (which you should be if you've been married 5 years), you may want to consider that first. For me, it only took 3 months from start to finish but I know it can take longer in some offices. I was working on learning about the Canadian PR sponsorship process and paperwork for my husband at the same time, which took months anyway. The Canadian paperwork is quite a bit more lengthy and complicated, IMHO.
Anyway, I became a U.S. citizen in January and we still didn't have the Canada immigration paperwork ready to mail until the end of February. We applied outland so the file will be processed in Buffalo which is usually quite a bit faster than applying inland through Vegreville, AB. Your husband needs an FBI clearance and that can take up to 16 weeks to get although we lucked out and got ours back in just 4 weeks.
I'm not sure what your husband's employment situation is. We were in a situation where I was working full time and my husband was a stay at home dad for the last couple of years in the U.S. We had a business that failed back in 2008 and lost everything so we didn't even have any real assets in the States and had been renting. I was worried about that because our plan was to come to Canada in March and we also did not want to be separated, but I was concerned about him not having enough "ties to the U.S." (like property or a job). We have 4 children, all born in the U.S. and I was able to apply for their Canadian citizenship cards so they were entitled to come to Canada with me but it just wouldn't work if my husband couldn't come too because he was the one who cared for them while I was at work.
You do have to show proof of your intention to move back to Canada once your husband is granted PR status. For us, it was easier for me to find a job in Canada first and just plan to move so I could put that on the application, rather than stay in the U.S. and not have any idea when his PR would be approved and therefore when to start looking for a job. However if my husband had had a job, we would likely have stayed until the process was complete. As it turned out, I accepted a job in Saskatchewan and we came up here in early March. We left most of our stuff in storage in the U.S. so as not to throw up any red flags at the border and the border officer granted my husband a 6 month visitor visa, which isn't even technically necessary but we took it. Our hope is that he will get PR status before the visa expires but that is out of our hands and our file is in Buffalo waiting to be processed. It stinks to not have the majority of our stuff here though. We have been in a furnished place since we arrived but we have to move into an unfurnished place this week so we have been hitting the garage sales hard!
We did import both of our vehicles and one was pulling a u-haul trailer and the border officer didn't seem concerned about it. The vehicle import process is a whole other story.
Hope this helps. This forum is a wealth of info to help you through the process!
Also FYI, because we had a definite move date when I applied for my kids' Canadian citizenship cards, the lady at the Canadian Consulate where I applied requested expedited processing and we received their cards in about 2 months....sweet! It helped to have them when I applied for their Sask Health cards here.