location is a reserved word and may not be used as the name of a variable.
The HTML newline character is <br> not \n.
var adjective = prompt("Enter a adjective: ","");
var locn = prompt("Enter a location: ","");
var firstName = prompt("What\'s your name: ","");
var color = prompt("What\'s your favorite color: ","");
document.write('Last night I visited the ' + adjective + ' restaurant I have ever been to.');
document.write('<br>It was located right in the middle of an ' + locn+ ' just outside of town.');
document.write('<br>The name of the place, \"' + firstName + '\'s,\" was lit up with big ' + color + ' lights.');
prompt() and document write() have long been obsolete, and should be used (if at all) only for testing and debugging purposes. Use DOM methods to get input from and display messages to your users.
Note how to escape an apostrophe.
I expect you can see how this script does not attempt to ensure that the user entries make sense, or indeed require any entry at all. If so you have learned something important - input validation is often 80% of a practical script.
Please do not make any more posts asking us to do your homework for you. Pretending that other people's work is your own is normally regarded as cheating. Dishonest, in fact.
I suppose that what we are all waiting for is a picture of Kate with the baby coming out. - ITV Reporter