Take Boulevard Adolfo Ruiz Cortines towards downtown until the intersection with Lazaro Cardenas, which is just another name for highway 180 that passes through downtown Poza Rica. Once at this intersection go left (south) towards Papantla. As you walk or take a cab (about USD 1.00)you should see signs for Papantla and Veracruz. If not, you've messed up. Take this road until you get about two miles towards the outskirts of Poza Rica. At the first speed bump (tope) get off there. There is a curve just beyond it and all traffic is going towards Papantla, Costa Esmeralda, and Veracruz.
Places to avoid
Accommodation and Sleep
Along Lazaro Cardenas (Highway 180 passing through downtown) going south towards Papantla there is a park area with soccer and baseball fields. There are bleachers and plenty of places to call home for the night. It is a calm place with almost no visitors in the wee hours.
Other useful info
Poza Rica is a city built upon the shoulders of Pemex, the largest oil company in the country. The quality of life here tends to be a bit higher and it is probably one of the safer places in the country. Strip clubs and bars aren't the cartel hotspots as they are in many other cities.