So you want to do the change in Freeway? Then as long as it’s a table cell content, you can’t do that. If you wrap it in a DIV inline within that table cell, then you can turn the DIV off (and the content will hide with it).
Double-click into the table cell and choose Insert HTML Item. Double-click inside that item and type your text. Then click away elsewhere, and click once on the DIV inside the table cell. Use the Inspector to turn Publish off.
Yup, you’re right. I didn’t try that, it was off the top of my head.
Here’s something I’ve tried. In the Styles palette, use the cog menu to create a new style. In the Tag field, enter td.hidden * (don’t skip the trailing asterisk). In Name field, delete whatever Freeway has helpfully given you, and then tab out of the field so it sticks with your decision. Then click the Extended button, and enter display in the Name field and none in the Value field. Next, create a second style, and in the Name field enter hidden. You don’t need to add any other styles to this style rule, just having it allows you to mark the cells you want to hide. Click (and shift-click) on the styles that you want to hide, and then click on the listing labeled .hidden in the Styles palette list. That’s it, no more steps (and no inline DIVs) needed. When you want to remove that style later (to show the name) you can click once on the cell and then look in the (T) tab (far right) of the Inspector. There, you will see all the styles applied to that cell. As you hover over the hidden class name, you will see a little (x) appear in its name, and you can click that to remove that style without changing anything else.
You could also create a text style with the display: none thing in it. Erase the first style (td.hidden *), and open the second one (.hidden) and add the Extended display: none to it. Now, instead of adding the second style to the table cell, triple-click on he name and apply the style to that. It will disappear (and be unselectable) in the browser, but will be visible in Freeway.