Sounds wonderful. I think if you dig down that deep you don't need to put landscape fabric under the gravel - unless you have a root spreading invasive like that weedy (but pretty) campanula, or wild anenome. The weeds are going to grow by seed in the sand as you probably know. But at least they will be easy to pull up.
Kathy

I'm concerned about your step #4. Unless you lay your irregularly shaped rocks flat and even with each other, it will be tough on the feet to walk on. I did a walkway the way you describe and the uneven surface means I have to concentrate when I walk on it to avoid tripping.

Thanks concretenprimroses and dian57. I couldn't believe myself that I forgot this thread. I'm so sorry.

My wife and I have been searching the internet for stones with no luck. Someone told me to use "stone suppliers" as my search criteria.

About #4, I'm laughing about what I mentioned. I should have mentioned flat irregular shaped flagstones or fau flagstones rather than rocks.

Is there any online calculator for crushed stones/sand if we have the given?

300 sqft
4 inch high

Is it called crushed stones or just gravel? Or are they the same?