A couple of things to consider.
This horse had to be big enough to fill with enough men to take an entire city
These men would of needed enough ventilation to breathe (so holes to see the men would have been on the horse)
This is of an era pre showers (that many men would of had to of had a massive stink)
When bringing the horse into the city it would of been obvious the horse wasn't hollow due to the weight.
Tools in that era werent good enough to build a massive horse without any gaps
While it's not specifically about the details of the Trojan Horse, you may enjoy this essay by /u/iphikrates which discusses what historians of ancient Greece think about the whole of the Iliad: Why do some historians completely dismiss the Iliad and Homeric epics as having any historical basis?
The horse only needed to be big enough to hold enough men to take the gatehouse. Once the gate was open, the rest of the army could take the city.
And, yes, the men probably did stink a bit. But the city probably stank a bit too. Locals would be so used to the smell that they might not notice it.