When I lived in the U.S. some Spanish native and heritage speakers used to turn common English words and phrases into a non idiomatic form of Spanish. This is called Spanglish, hence words like rufo (roof) for techo, fenza (verja) for fence, constipado (extreñido) for constipated. The same goes for phrases like it stinks used as apesta. Spanglish isn’t viewed as “correct”. Educated native speakers avoid it altogether. However, people do speak like that and there’s a reason for it... well more than one but that’s another story.
Since we're talking about writing here, I think it's all about the character and writer's style. Spanglish can give a character a unique perspective. If the character is a Spanish native or heritage speaker living in the U.S. and s/he into Spanglish or if it’s culturally acceptable where s/he comes from, them the phrase este lugar apesta meaning it tinks/sucks/blows is okay. Otherwise, I don’t think it sounds right. I was brought up in Puerto Rico and I don’t remember ever using the expression esto apesta as in this sucks/blows/stinks. Maybe it’s different now. I don’t know. I’ve been living in Oz for 20 years.
Depending on how the OP is writing the story, her character can use other idiomatic or natural-sounding expressions to show how disgusted she's with the place (este sitio me tiene harta, yo no soporto este sito... no puedo más con este sitio...)
There's a bit of flexibility when it comes to writing fiction too. For instance, Dominican-born writer Junot Diaz has a very interesting writing style. He mixes Spanish (Dominican) with English in his stories and it works- well, at least I think so. The reason it works well (IMO) is because it feels natural.
Here's an example:
For what Kennedy's intelligence experts failed to tell him was what every single Dominican, from the richest jabao in Mao to the poorest güey in El Buey, from the oldest anciano sanmacorisano to the littlest carajito in San Francisco.
