Way back is used for 'long ago'.
Check OxfordDictionaries's entry way back (informal)
Long ago Your sentence sounds strange to me with those words in it.
Don't use it that way.
Probably , you are confused with this - make one's way back (to something) - to work one's way back to something or some place as in ...
I made my way back to the little town in the densest fog I have ever seen.
I went for a walk and got lost.
It took hours for me to make my way back.
So, read the entry and clarify your doubt! :)
ell.stackexchange.com/users/3187/Maulik V
You can simply say Have a safe way back! if you mean to wish someone a safe trip back to the place from which they have come.
"Have a safe trip home!"
is probably the most common expression.
In my neck of the woods we say things like: Have a safe trip back home.
Have a safe trip back.
Have a safe way home.
Have a safe way back.
We're looking for a safe way back home.
Many of the roads are flooded.
Here's an attestation of "Have a safe trip back": And here's an attestation of "a safe way back home".
In my AmE dialect, "way" can mean both "route" and "trip/journey".
ell.stackexchange.com/users/10264/Tᴚoɯɐuo
The use of an article (i.e. " a ... way back" in your sentence) makes it unambiguous.
The phrase "way back" referring to a time long ago is an adjective phrase and does not accept an article - or, for example, a possessive pronoun, as in "my way back" in Maulik V's example.
I should note, though, that the way somewhere generally refers to the route , not to one specific trip.
I think this is the reason the others are reading your sentence as being awkward.
And I don't know about other dialects, but "back to home" is incorrect for American English, and should be "back to your home" or "back home".
ell.stackexchange.com/users/402/Random832
"way back" is an idiomatic expression for "long time ago", short for "a long way back in time".
For example: "When did you meet Joe for the first time? "
"That was way back when I still was a teenager".
In your case, you are using by coincidence the word "way" followed by the word "back".
You could have said "wish you a safe journey back home", or "wish you a safe travel back home".
It has nothing to do with the idiomatic expression and is fine to use.
Dan Bron's suggestions are slightly better, but not to a degree where your sentence would be wrong.
"Wish you a save way back home" sounds maybe a bit too worried that something could go wrong.
Of course if you are a bit too worried then the sentence is exactly correct.
ell.stackexchange.com/users/6338/gnasher729
The phrase way back has two primary meanings, as others have pointed out.
Using way back can be used to refer to a long time ago, such as "way back when.
" In this instance way is describing the word back as being very far back.
How far back was it?
It was way back.
This meaning could also be applied to distance, meaning that something was a very long distance back on a path.
Using way in this sense is fairly colloquial, not often found in formal writing.
The other use of way back is to refer to a specific path taken.
In this case back is modifying the noun way , and often includes a destination.
Which way did he take?
He took the way back (to the house).
This implies that the path in question has already been traveled once, but you are now returning.
Your case more closely relates to the second definition, though most people would not use it that way.
Instead, I would simply say Have a safe trip home!
ell.stackexchange.com/users/19446/David K
Can I say:   Wish you a safe way back to home   when I am trying to tell someone I wish them to return home safely? When I was googling, I saw that there is another meaning for the phrase  way back , which means  long ago . Because of that I'm unsure whether I am using it correctly in my sentence. Does my sentence sound ambiguous? If yes, how can it be rephrased?
How do I use the phrase "way back" properly?
ell.stackexchange.com
<grammar><meaning-in-context>
ell.stackexchange.com/questions/56122
ell.stackexchange.com/users/13924/Kushan Randima
You can say "Have a safe way back!" "Way back" can also be used to refer to a long time ago, as in "way back when". The other use of  "way back"  is to refer to a specific route. Way back can refer to a long time ago, as well as returning on a specific path.
Way back can refer to a long time ago. Way back can refer to returning on a specific path.