I have an approved US petition but it's taking forever for that elusive interview. Now, I have an approved multiple tourist visa. Is there another way for me and my family to just go there and work right away and probably convert that visa to a working visa and eventually wait for that interview in the US to come along?
No, you should not enter the country on your tourist visa to work ahead of your interview. It's not allowed, very possibly might not work, and could have serious repercussions for your immigration process. You are allowed to visit the US with your tourist visa, but
- you can't work while visiting
- you might be refused entry anyhow
I don't think there is any other option, aside from your tourist visa, for you to enter the country before your interview. (Checking the list of all visa types, I don't see any other visa types you could apply for to arrive earlier.) When you have your interview, that will lead to a new visa, which will allow you to immigrate to the US.
Working while a tourist
The State Department says, "Visitors are not permitted to accept employment or work in the United States." So if you were to enter the country as a visitor, and then work, you
- would be working illegally
- would be breaking the terms of your visitor visa
There can be repercussions for this. For example, according to the instructions for Form I-485, anyone who "[was] employed in the United States without USCIS authorization prior to filing this application" is "not eligible for adjustment of status". ("Adjustment of status" is a process where a person already inside the US switches from being a visitor to being a resident.)
Entering the country
If you were to enter the country ahead of your interview, there's a real chance you could be denied entry. A CBP officer will ask you what you're intending to do on your trip, and where you'll stay. They will know that you have a petition and are waiting for your interview. If they are not convinced that you'll be only a visitor, they can refuse you entry.
If you make untrue statements about what your plans are to a government official, such as that CBP officer, this can be considered willful misrepresentation or fraud. If caught, those make a person inadmissible to the United States in the future. Being inadmissible to the United States means no visas, residence, or entry to the US in the future (without a waiver). You'd be risking your path to residence via petition.
You can read more about what the USCIS considers "fraud" or "willful misrepresentation" in their Policy Manual. But for real advice about the relative risks and legalities of things like this, you should consult a knowledgeable lawyer.