Woostine:As mentionned above evereyone has its own experience.
I met my husband in the summer of 04' while visiting my godparents (visa waiver program). We barely spend time with each other, but enough to start dating and fall in love. I had to go back to France at the end of my vacation though.
Did't see each other for 7 months, but we email, mailed and called each other twice a week. We learned so much more about each other that way. We were already in love and with a complete trust in each other.
I came back in March 05 for an internship (J1 visa). I had a 4 months internship to do for my degree and I made sure to have it in his area so we could be together and we moved in together for the 5 months I was there.
Went back to France in August and came back for a two week-vacation in December.
Left again, not sure for how long.
I was completely miserable without him, so I decided to come back when came June, bought a plane ticket for July and came back with a B2 visa I had since 2000. Moved back together.
My goal was to find a job, interview and then go back to France to obtain the visa. Well, it didn't work out. I had lots of job offers, however obtaining a work permit was much, much, much harder than we had imagined.
After 5 months, I renewed my B2 (you can do that once). We were under pressure to get married by our families but we were not ready.
More job search. More no because of work permit.
The last no was in June 07, I had less than 2 months left in the USA and neither one of us could stand the thought of being apart again. So we just decided to get married. Back in March we had considered the K1, but then realised that since I was in the country legally, we could easily just get married and apply for AOS. That's what we did in July at the courthouse.
I then got a work permit within 3 months and started working.
I received the Green Card a year after in July 08.
And we are having our wedding ceremony with both families this November.
My advice: if you have the option to come with a J1 do it, that's one of the best choices you have. The other choice is a tourism visa, but it's not recommended to do that if you know you want to get married while in the US and apply for AOS following it.
Sadly there are very few choices for people who love each other.
After months of pondering what we were going to do, we came to the decision that getting married and applying for the green card was our best option. I've never regretted that choice.
FerlineAs far as family is concerned, well I didn't really have a talk with them since I didn't know we would get married when I came back. But they are happy for me as long as I'm happy. They'll finally meet my husband in less than a month.

There is no suspicion whatsoever when you do a courthouse wedding after the K1. Immigration knows that there is only a short window of time to plan and have the wedding once the visa is approve and I believe they know that most people do a simple courthouse ceremony. Many people plan a bigger family wedding later on and if that's your case, bring proof of that to your interview.
We had a courthouse wedding and I was here under a B2. We had family with us and it was a small wedding but not just 2 witnesses and us either. I had a white dress, a bouquet and my brother as a witness. I was never even asked questions whether we would have a big wedding after that or not. I believe it helps that you have friends and family with you, and pictures that show that you celebrate it, but it's not essential.