Been there. 3 kids, low budget, wanting to get the wife and daughters off the ground and out of tents. Well, that's DW saying the last point.
Funny thing is back then with all the kid's we used a pop-up. Now that we are empty nesters we have a 32' FW with all the comforts of home. Go Figure.
Point is, for many of us it was an evolutionary process. For us personally we are on our 4th camper in 22 years and they keep getting bigger with each purchase. We do what we can with what we have at that point in our lives to travel and camp. Your answer to get off the ground is either more money & more truck or a pop-up.
On Edit: We started off in the early 1990's by renting pop-ups for ~$70/night. Your $4000 could represent 300 nights of rental payment if you can find a rental your vehicle can tow.